Given the Question and Answer pair, detect whether the answer is acceptable or not. Denote acceptable answer as "yes", otherwise denote as "no". An acceptable answer is consistent with the context in question, detailed, long, and uses general knowledge of English. Answers that are not definite and suggest a variety of options are not acceptable answers.

Question: This came up recently on programmers.SE, when someone (a Russian, presumably non-native English speaker) asked why we used the term "sister sites", instead of "brother sites". Of course, I'm a native English speaker, and I have no idea either, hence this question. The full question, for context, was "Several of our sister sites have taken to featuring Questions [...]". It does seem odd, considering that English (usually) uses masculine terms as the default.
Answer: It is because only female carries the direct increase/multiplication through reproduction; that's why we also say mother tongue.
no

Question: So basically, I know the name for both sides of a coin, yet not the coin itself. In other words, when you refer to a coin, you don't want to say 'this object with one side heads, and the other tails', you would want to say 'this coin'. What I want is a general term to refer to two ideas, that are the absolute opposite to each other. I can't really use the word 'concept', or 'idea', because such words are already assigned to the very concepts/ideas themselves.
Answer: Dichotomy. =] More generally, not limited to two ideas or opposing ones. Abstract concept or meta concept. In programming, we usually refer to it as a class, parent class, or abstract. Note that Abstract concept or meta concept can refer to something with more than two species, and to things that aren't limited to opposing species either. It's even more general / abstract ;).
no

Question: Possible Duplicate: "Did it close" vs "Has it closed"? As a English non-native speaker it is difficult for me to understand when I must use present perfect or past simple because in my official language there isn't the present perfect tense. I know that present perfect is related to something that happened in the past but its result is important now. But for instance: The message has been sent. The message was sent. Please help me point me out any examples/contexts where I should use 1. instead of 2.
Answer: 1 means that the action happened just now. You would typically see it in your e-mail program just after you send an e-mail. Your program might give you this message to let you know that the message you just sent has indeed been sent. 2 refers to something that happened at some time in the past. It could have been an hour ago, a day ago, or even a century ago! But it wasn't just now.
yes