单选题：I don't know _____ he gets along well with his lessons.[ ]..

— Did you remember to return the money you owed to Mary? — Yes, I gave it to her _____ I saw her.A. while B. once C. suddenlyD. the moment

Experts are trying to work out a solution to save the miners _____ its too late.A. before B. sinceC. unless D. when

— Anything else should we pay attention to if we go camping? — Nothing much.Just take a raincoat _____it rains.A. in case B. as if C. even if D. so that

I don't know why she's looking at me _____she knew me. I've never seen her before in my life.A. as B. although C. as if D. even if

We should keep an open mind about some strange old wives' tales, _____ they do have some truth in them.A. and B. so C. because D. until