instruction:
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.
question:
Consider the following sentences: The last few years has seen the building of the new church. and The last few years have seen the building of the new church. As a native speaker, both of these sentences 'sound' correct to me. Is only one of them correct, are they both correct or is each one only correct in specific circumstances. This was a question one of my students asked me, so if there is a relevant grammar rule, that would be great.
answer:
Years, being plural, takes the plural form have. But the last few years, being a single span of time, takes the singular form, has. That's why they both sound okay to you. The first option is generally preferred in formal writing.

question:
In technical literature as well as aircraft user interfaces where there is not enough space to write the whole word, the prefix 'trans' is shortened to 'x'. Transmit -> Xmit Transfer -> Xfer I am interested to know what is the origin of this. I am curious because 'Ex' and 'Trans' do not have a similar sound.
answer:
X is commonly used to refer to cross because of its shape of two lines crossing. Trans- means cross/across. Trans- and cross- are interchangeable in many cases. From Wikipedia (emphasis mine): In abbreviations, it can represent trans- (e.g. XMIT for 'transmit', XFER for 'transfer'), cross- (e.g. X-ing for 'crossing', XREF for 'cross-reference'), Christ- as shorthand for the labarum (e.g. Xmas for 'Christmas', Xian for 'Christian'), the crys- in 'crystal' (XTAL), or various words starting with ex- (e.g. XL for 'extra large', XOR for 'exclusive-or'). Example: a transatlantic flight is one that crosses the Atlantic, and something that is transdermal crosses through the skin. The trans- in transmit and transfer is analogous to transatlantic. Crossing a mit or a fer makes perfect sense. -Mit is from the Latin mittere which means to send. -Fer is from the Latin ferre which means to bear or carry. 'Transmit' often means to send across something or over a specific medium and 'transfer' can be to carry across from one to another. Therefore trans- is often replaced with X- in certain words.

question:
is it 'a usual' or 'an usual'? 'A usual' sounds more correct in my head ('Today was a usual day.') than 'an usual', but u is a vowel. Which one is correct and why?.
answer:
Usual (pronounced /ju.u.l/ as in you) begins with a consonant sound and, as such, it should be preceded by a not an. As an aside, I cannot help but point out that the sentence Today was a usual day is not usually heard in regular conversation. Today was an unusual day is what one might hear, instead! Indeed, I rarely hear the construction a usual. The definite article is more commonly used, in my experience: That's the usual thing. In place of a usual, one would also be more likely to hear not an unusual: Today was a usual day / Today was not an unusual day This is a usual occurrence / This is not an unusal occurrence or This usually happens You are right in saying that a usual sounds weird. As speakers, we tend to avoid constructions which, though correct, do not flow easily from the mouth. In sum, the following are valid and commonly used alternatives: not [an] unusual the usual usually