'a' is used before words that start with a consonant sound and 'an' is used before words that start with a vowel sound :-) So we a cat, a table, a university (the u is pronounced like 'you') and an apple, an egg, an hour (here the 'h' is silent') :-)

I haven't finished it yet. (negative sentence) Have you finished it yet? (question) - present perfect Hope this helps! :-) Sara

In answer to the first question, I wouldn't say any of those phrases as a native British English speaker, I would say: 'There was no point me (us) getting here so early/leaving home so early' In answer to the sound question, I'd say "Could we go/walk back down that's a block back from the waterfront" Hope this helps! Sara :-)

Former = the one before or one from the past e.g. the former president prior = This word is formal. It means before, existing or happening before something else, or before a particular time: e.g. The course required no prior knowledge of Spanish. = No knowledge of Spanish beforehand :-) preceding = existing or happening before someone or something, e.g. In conclusion, I hope the preceding arguments have convinced you of the need for action. This word is also formal. Hope that helps!

Primary = main or most important. and in this context, foremost= the most important. So, the meanings can be considered the same, but primary can also have the meaning or being the key one, the one that is the main focus. Hope that helps! :-) Sara

Either 1 or 5 or a combination of the two. The others don't sound quite right, either too abrupt or the word choice just doesn't sound natural.