Generate the answer for a given question. The question requires common knowledge of English. Make sure that the answer is in detail, long, consistent with the context, and requires general knowledge of English. To be less repetitive, please vary your language for each question. Give a proper explanation to answer, and if necessary, provide the definition of various terms. And conclude your answer if it's long. If you have used other resources (e.g., Merriam Webster's.) to answer the question, include citations in your answer. You don't need to paraphrase the context of your resources, but make sure that your answer is consistent and complete.

[Q]: I'm wondering which one of these expressions is correct? This stuff or these stuff?.
[A]: Stuff is a collective noun it represents a group of objects. Just as one would say 'this group' or 'this pile,' one would say 'this stuff'.


[Q]: What can I call someone (a friend) who is always asking for favours such as: if you are going downtown, can you buy this for me please or, can you lend me your car for an hour or, if you have some spare time, can you post this letter for me please because I am so busy today He doesn't seem to realise or, pretends not to, that there is a limit to asking for help or favours from other people.
[A]: He may be called a moocher. It is used for a person who tries to get to something free of charge.


[Q]: Possible Duplicate: Do you use 'a' or 'an' before acronyms? Does one use 'a' or 'an' before the word 'X-Ray'? Quite simply, should a sentence read 'a XML report' or 'an XML report'?.
[A]:
It's 'an XML report', because which form of the indefinite article to use is decided by how the next word is pronounced. In this case, it's pronounced: An ex-emm-ell report 'XML' begins with a vowel sound, 'e', so an is used rather than a.