下列各句中表达得体的一句是（ ）

I have experienced quite a number of cases ______ I really wanted to help but could not find anything to _______ [ ]

Smoking, ____ some smokers, might ease their anxiety sometimes, but ____ the addiction caused by their constant practice, it is really hard to give up.

If the dog hadn’t woken us, we wouldn’t have noticed the fire and it _____ to the house next door.

_______ maps are there —- There are eight.