I'm sometimes confused about the difference between present perfect and simple past sentences such as the ones in the title. In what kind of situation  do you guys say "Where have I parked my car" or " Where did I park my car?"   Thanks in advance.
If I seem tired, can I say: "I haven't slept last night"? If not, why have I been told that we use present perfect for actions that have present effects?
What are our policies regarding self-harm and suicide? What should I do as a Moderator when I encounter situations regarding self-harm and suicide? I have a question.  I have been given this proof: "For any $n$ in the integers where $n&gt;2$, show there are at least $2$ elements in $U(n)$ that satisfy $x^2=1$."  I have gone through and actually proved this, (that the numbers are $1$ and $n-1$) but i didn't' know how to prove that $n-1$ is in fact in the set $U(n)$. Is it because two consecutive numbers are always relatively prime? In node.tpl.php, I have done some changes, like creating an array of paragraphs:      $paragraphs = explode("&lt;p&gt;",render($content));   So, I have a for loop for showing the paragraphs, like:  $number = count($paragraphs); if($page){   print render($paragraphs[0]);   for ($i=1;$i&lt;$number;$i++)       {          print render($paragraphs[$i]);        &lt;a href="#commenting"&gt;Put comment for Paragraph &lt;?php echo $i?&gt;&lt;br&gt;&lt;/a&gt; &lt;?php  } ?&gt;     &lt;a id="commenting"&gt;&lt;?php print render($content['comments']); ?&gt;&lt;/a&gt; &lt;?php }?&gt;   As you can see I want to create a hyperlink under each paragraph, so when user click on it, they can put comment on the paragraph, But right now, when they click on the hyperlink, it will  jump to the end of the page, which has the comment form.  If you check the CommentPress website, in the right column, you can see for example, it is said: 5 Comment on Paragraph 1, and when you click on it, it will show the comments and the comment form under that link, I want to have the same thing, I mean, when users click on the link under each paragraph, the comment form displays under that link instead of jumping to the end of the page. I need to analyse data and am unsure whether or not I should use a multinomial logistic regression analysis or a binary logistic regression analysis. I have just conducted a latent class analysis and am interested in seeing if my variables can predict class membership. There are only two classes and so my response variable only has two categories; however the variables range from having 2 to 3 to 4 and are mostly nominal categorical data. I'm working on a project using logistic regression to predict student retention. The data were collected through three self-report instruments. We are trying to find out which predictors are powerful enough to predict the at-risk students. I came across some articles saying a balanced sample (50% stay, 50% dropouts) is desirable for such study, e.g. Glynn, J.G., Sauer, P.L., &amp; Miller, T.E. (2003). , NASPA Journal, 41 (1), 41-67:     A problem however, is that the distribution of the dependent variable is likely to be highly skewed toward persistence. For example, if 85% of the analysis sample were persistors, a classification model that classified every student as a persistor would have a success rate of 85%, or would classify 85% of student correctly. To resolve this issue, the maintenance of relative balance between the number of dropouts and the number of persistors (about 50% each) in the analysis sample was desirable.   Is this true? Our sample only has about 25%-30% dropout students. Will this affect the results? Should 'fuck' be present in review audits (intentionally fake suggested edit reviews)? Some suggested edit reviews are fake and are intended to check that the reviewer is paying attention and reviewing correctly.  I recently encountered one where the fake suggested edit contained 'fuck':   Despite the fact that we regularly encounter profanity online these days, and whilst it is not uncommon to encounter the word 'fuck' in blog posts by recognised authorities in the world of software development (and, I assume, in other fields), this nevertheless caught me a bit by surprise.  I have no problem with whatever strength of language someone feels is appropriate and relevant to make their point, however in the context of audit-related fake suggested edits, is the use of profanity appropriate?  Update: just to clarify, the word 'fuck' was not present prior to the fake suggested edit. The fake suggested edit added the word 'fuck' where it was not previously present. Is adjoint of singular matrix singular? What would be its rank? When does the 'Lost City' become Atlantis in Stargate In Stargate SG-1 they are searching for the Lost City in season 8, however in the Stargate Atlantis pilot it is referred to as Atlantis. When is the name found? Or the connection between the Lost City and Atlantis made? Determine the SQL Server version and edition from the available set up, before actually installing it? I have a dual boot of Windows 10 and Ubuntu 16.04. Recently I upgraded it to 18.04. As soon as I did it, it started showing DISK IS LIKELY TO FAIL SOON (37° C / 99° F).    I checked the status of my disk via Windows and it shows it’s perfectly healthy. I assumed the error occurred because my partition size of Ubuntu was 64GB (which I now increased to 86GB). Please help me out with this.    Edit: The results of smartctl - attributes My months and days in my File Manager are in German, how do I change that? On the photo you see 'Dez' : It means Dezember (German for December). I also saw one day Mittwoch (German for Wednesday). How do I change that German issue? This is only my File Manager and not completly but partially. Weird. When Ron broke his wand, why didn't he apply for Hogwarts financial aid? We know, from Book Six, that Hogwarts has a financial aid for students in need. It's supposed to cover all expenses regarding materials and school supplies, so it certainly covers wands. So why didn't Ron simply apply for this fund when he broke his wand in Book Two, since his family could not afford a new one?  Seems absurd that no teacher would notice that Ron had a broken wand and inform him there's a school fund. Plot hole?  Obs.: Even if Ron could afford a new wand, one could ask how we would purchase it (you must experiment personally to find a wand that chooses you). It turns out that there's a local branch of Ollivander in Hogsmeade. I'm sure that, under those circumstances, a second-year student like Ron would be allowed to visit Hogsmeade to purchase a new wand. When trying to restore a backup to a SQL Server Express 2008 database I got the following error:  Restore failed for Server '...\SQLEXPRESS'.  (Microsoft.SqlServer.SmoExtended) System.Data.SqlClient.SqlError: The database was backed up on a server running version 10.50.1600.  That version is incompatible with this server, which is running version 10.00.2531.  Either restore the database on a server that supports the backup, or use a backup  that is compatible with this server. (Microsoft.SqlServer.Smo)   Is there a way to get a backup which is compatible with the older (in my case 10.00.2531) version from the newer (in my case 10.50.1600) version of SQL Server Express? From the user's perspective when switching on the phone, I see two boot animations in my  running CM10. The first animation is from LG and the second animation is from CM10. Then it settles in with a locked screen ready for my input. What happens behind the scene (screen) during a boot process when an Android device is switched on? It will be helpful if the answers can help a non geek to understand various process and jargon (like, fastboot, bootloader, recovery, if applicable, etc.) regarding boot sequence. How to model the curly cable part of the phone Hello. I am a beginner in Blender. I started modeling this phone and when I got to the curly cable part it was a real challenge. Could someone guide me on this. Case-insensitive string comparison in C++ What is the best way of doing case-insensitive string comparison in C++ without transforming a string to all uppercase or all lowercase?  Please indicate whether the methods are Unicode-friendly and how portable they are. How to revert to tabbed overview in Chrome? I recently updated my Chrome for Android (currently on v68) and noticed that tapping on the box icon (next to address bar) gives a tab list instead of SystemUI type overview that Chrome used to give. See the two images below for comparison.  I know that I can get that same view by swiping downwards from the address bar but I'm habitual of getting it from that box icon.   So what can I do to get back that view from that box without reverting to a previous version of Chrome and without switching to an another browser (unless it is Chrome based)? How can I show that the set of rational numbers with denominator a power of two form a dense subset of the reals? How can I show that the set of rational numbers with denominator a power of two form a dense subset of the reals? $H$ is normal subgroup of $G$ iff $gHg^{-1}=H$ for every $g$ of $G$ Given the following definition of normal subgroup     A subgroup $H$ of a group $G$ is said to be normal if, for every $g\in G$: $$gH=Hg$$   I've tried to show that $H\mathrel{\unlhd} G$ if and only if we have $gHg^{-1}=H$ for every $g\in G$:  (if) Let $H\mathrel{\unlhd} G$, $g\in G$; if $l\in gHg^{-1}$, there exists $h\in H$ such that $l=ghg^{-1}$ and since $gh$ = $h'g$ for some $h'\in H$, then $l=ghg^{-1}=h'(gg^{-1}) = h'\in H$. Let $h\in H$; we can write $h$ as $hgg^{-1}$, and since $hg = gh'$ for some $h'\in H$, we obtain $h = hgg^{-1} = gh'g^{-1}\in ghg^{-1}$. So $gHg^{-1}=H$.  (only if) Let $gHg^{-1}=H$, $g\in G$; if we take an $l\in Hg$, $l = hg$ for some $h\in H$, we note immediately that $l=hg=(gh'g^{-1})g=gh'\in gH$. What should I do to show that $gH\subset Hg$?  I'm also wondering if this mess is correct, and if it is possible a more elegant proof of this fact. I can follow the proofs in which the asymptotic normal-distribution of a maximum likelihood estimator $\tilde{\theta}_n$ is derived.   however, does this already imply that the maximum likelihood estimates are asymptotically unbiased, i.e. do we have $$E(\tilde{\theta}_n) \to \theta \text{ as } n \to \infty?$$  Since I am aware that in general it is not true that convergence in distribution implies convergence in moments, an explanation would be nice.  The result is often stated e.g.  as "...it means that the bias of the maximum likelihood estimator is equal to zero up to the order $n^{-1/2}$")  1.) Are  some kind of regularity conditions from the mle theory used to establish this result?  2.) Or is a $\sqrt{n}$-convergence of an estimator (to a normal distribution) in general already enough to establish convergence of its moments?  Note: the Wikipedia article mentions Cox, David R.; Snell, E. Joyce (1968).  , as a source where the order of the bias is derived (formula (12) or (20)).   However in this paper I can't follow the arguments 100%, since their Taylor approximation of $L'(\widehat{\beta})$ is lacking the remainder term. What is the argument used here to discard it completely?