It was quite a serious mistake, ____caused by carelessness.
For a moment nothing happened.Then ________ all shouting together.
Only after Mary read her composition the second time ________ the spelling mistake.(2012·天津)
Never before ________ seen anybody who can play tennis as well as Robert.(2012·江西)
Every day________a proverb aloud several times until you have it memorized.
It was with the help of the local guide ________ the mountain climber was rescued.