In English, it is customary to refer car as "she". Of course, if you talk about someone else's car you simply use "it". The same happens with ships. For any common person, a ship is neutral, but for the Captain and the crew, it's a she. Hope

In Standard English, a1 and b2 are correct. Cheers!

In this case, you are not talking about possession; you are refering to a whole family, so the last name (or surname) is pluralized without any apostophe. In such a case, the second sentence is the right one. Cheers!

As Maj says, monosyllabic words ending with a consonant inmediatelly after a single vowel double the last consonant when a suffix like "ing" or "ed" is added. Thus, we write "sitting" and "canned". However, this also applies to two-syllable words

Almost. "Since we were behind schedule, we had to work quickly" is the proper one. Cheers!

IMHO, "all the spaghetti is gone" is the right one. The expression "all of" means "no less or smaller than". For example: "she's all of forty years old, no doubt". Hope this helps!

It's correct. The preposition "at" implies "temporarily", that's why we say "at school", "at the theater" or "at the movies". You eat "at a restaurant", but a waiter works "in a restaurant". Hope this helps!

It's Past Perfect.

Something similar happens in UK, for instance. If you watch the news on TV, you will hear a "neutral" pronunciation. This neutral, and sometimes arguably called "educated", accent is called "General American" in AmE and "Received Pronounciation"

"Toronto Maple Leafs" is a proper name, and there are no rules for names (as in Tolkien's "elfs" instead of "elves"). The plural of "mouse", either the animal or the gadget, is "mice". Cheers!