What is the difference? "Kate watched TV a lot when/while she was sick last year" What is the difference between these two sentences?   Kate watched TV a lot when she was sick last year. Kate watched TV a lot while she was sick last year.
When should I use "when" and "while"? But you can't find anything while you're crying.   But you can't find anything when you're crying.   I'll tell you about it while Frank saddles the horse.   I'll tell you about it when Frank saddles the horse.     When should I use when, and when while? Are these sentences correct?
Is it possible to batch import Wavefront .obj to blender? I'm working on 2.69. If I select multiple .obj files, only one gets imported. Also if I hit A on file selection window to select all files (.obj and .mtl) I get an error, nothing gets imported. I have to import several hundreds of .obj into the blender file, is this possible? Why are packages in the official Ubuntu repositories older than the latest (upstream) versions from Debian Sid, PPAs, the authors, etc.? If $a_{ij}=\max(i,j)$, calculate the determinant of $A$ If $A$ is an $n \times n$ real matrix and       $$a_{ij}=\max(i,j)$$       for $i,j = 1,2,\dots,n$, calculate the determinant of $A$.   So, we know that   $$A=\begin{pmatrix} 1 &amp; 2 &amp; 3 &amp; \dots &amp; n\\  2 &amp; 2 &amp; 3 &amp; \dots &amp; n\\  3 &amp; 3 &amp; 3 &amp; \dots &amp; n\\  \vdots &amp; \vdots &amp; \vdots &amp; \ddots  &amp; \vdots\\   n&amp; n &amp; n &amp; \dots &amp; n \end{pmatrix}$$  but what do I do after? Why must an English learners should know Grammar first? Why must everyone understand Grammar first before learning to speak? How to understand pipes When I just used pipe in bash, I didn't think more about this. But when I read some C code example using system call pipe() together with fork(), I wonder how to understand pipes, including both anonymous pipes and named pipes.  It is often heard that "everything in Linux/Unix is a file". I wonder if a pipe is actually a file so that one part it connects writes to the pipe file, and the other part reads from the pipe file? If yes, where is the pipe file  for an anonymous pipe created? In /tmp, /dev, or ...?   However, from examples of named pipes, I also learned that using pipes has space and time performance advantage over explicitly using temporary files, probably because there are no files involved in implementation of pipes. Also pipes seem not store data as files do. So I doubt a pipe is actually a file. I am studying statistics and I am wondering when it comes to standard error or a sampling if the calculation changes when there are weights added.   I have a weighted mean:  $$\mu_{w} = \dfrac{\sum_{i=1}^Nw_ix_i}{\sum_{i=1}^Nw_i}$$ and a weighted variance calculated by:  $$s^2_{w}=\dfrac{\sum_{i=1}^Nw_i}{(\sum_{i=1}^Nw_i)^2-\sum_{i=1}^Nw_i^2}\cdot \sum_{i=1}^N(x_i-\mu)^2$$  is the sampling error still calculated as  $$\text{SE}=\sqrt{\dfrac{s^2_{w}}{n}}$$ In the following example, is it appropriate to use a or an as the indefinite article, and why?     He ate __ green apple.   I know that in the case of just "apple", it would be "an apple," but I've heard conflicting answers for "green apple," where the noun is separated from the article by an adjective.  Also, which is more appropriate in this case:     He ate  __ enormous Pop-Tart. How to install Tor? I tried to install Tor on my new version of Ubuntu, but it seems that Tor is not available in the repositories.  How else can I install and use Tor? How can I stream the same music to multiple computers? Is there a way to stream the same playlist on multiple computers at the same time? I want to be able to sync what's playing on multiple computers (for parties etc). How to put a full-width table at the top or bottom of the same two-column page as the reference text? I'm posting today because I would like to reduce white space in a document I'm writing. The content is two-columns but I have floating tables that span across both columns (table*).   At some point, the text ends in the beginning of the first column of a new page. I would like to include my table on this page since it has a lot of free space below the text, but when I insert the table* right after the text, it goes to the top of the next page instead:    Do you know a way of obtaining the desired behavior?  Minimal working example :  \documentclass{article} \usepackage{lipsum}  \begin{document} \twocolumn  \paragraph{} \lipsum[1]  \begin{table*} \centering \begin{tabular}{|c|c|c|c|} \hline Column 1 &amp; Column 2 &amp; Column 3 &amp; Column 4 \\ \hline Column 1 &amp; Column 2 &amp; Column 3 &amp; Column 4 \\ \hline \end{tabular} \end{table*}%   \end{document} Tractatus 3.333 and Russell's paradox Can anyone explain to a non-logician how Tractatus 3.333 refutes (or fails to refute) Russell's Paradox? Please explain his use of symbols! What does "isomorphic" mean in linear algebra? Was Stack Exchange named after Experts Exchange? Was Stack Exchange named after Experts Exchange, or is the former using the word "Exchange" a coincidence? When you send a group text message in iOS, it appears as if you automatically opt in to receive any and all replies to that message. Is there a way to avoid being included in group replies? Is there a way to remove oneself from a group chat? In the Android App, if a question is closed, I won't be able to leave comments on either the question or any of its answers. There are simply no "Add Comment" buttons available anywhere if the question is closed.  See the screenshot below. The comment adding interface is simply removed on closed questions and their answers &mdash; no Reply button in the toolbar, and no Add Comment button under the question.        Occurs on Android app v1.0.50 and v1.0.51, on a HTC One running Android 4.4.3. Can I purge configuration files after I've removed the package? I was doing a package removal with apt-get remove but then realized I should have done a --purge along with it to remove the configuration files.  Can I remove the packages configuration files easily or do I need to reinstall the package and then remove with a --purge? How to get past a forgotten iPhone passcode? "He committed a crime killing/by killing a bird" Which wording with kill should be used here:     He committed a crime (killing/by killing) a bird.   My guess is the answer would be by killing. But I am really confused with the answer killing.   My questions relating to this sentence are:   Which one is correct and why? (or are they both correct?) If one of them is incorrect, why is it incorrect? (or, if both of them are, why?) If they are both correct, what is the difference in meaning? If they are both correct, what is the difference in their grammar? How to install applications to a separate hdd? I was so good with windows, now I’m feeling like a complete idiot.  I have an SSD for ubuntu and want to install the majority of my programs to a separate HDD but I have no clue how. All searches I have tried only turn up with dual-boot installations.   (RESOLVED -> ) I am also having trouble locating "/etc/". Specifically, to modify Conky. Searching for this term only turns up instances where people are telling you to access this file, not how to get to it. How does leave-one-out cross-validation work? How to select the final model out of $n$ different models? I have some data and I want to build a model (say a linear regression model) out of this data. In a next step, I want to apply Leave-One-Out Cross-Validation (LOOCV) on the model so see how good it performs.  If I understood LOOCV right, I build a new model for each of my samples (the test set) using every sample except this sample (the training set). Then I use the model to predict the test set and calculate the errors $(\text{predicted} - \text{actual})$.  In a next step I aggregate all the errors generated using a chosen function, for example mean squared error. I can use these values to judge on the quality (or goodness of fit) of the model.  Question: Which model is the model these quality-values apply for, so which model should I choose if I find the metrics generated from LOOCV appropriate for my case? LOOCV looked at $n$ different models (where $n$ is the sample size); which one is the model I should choose?   Is it the model which uses all the samples? This model was never calculated during the LOOCV process! Is it the model which has the least error?