It was a time _____ the killer whales helped the whalers catch the baleen whales [ ]

Is this the first time you _____Chengdu ?—–No But the first time I _____here, the city wasn’t so beautiful

Would you like Emily and Carol—Of course. I hear they are twins and play the piano well.

Money is a needful and precious thing, and when ______, a noble thing, but I never want you to think it is the first or only prize to strive for.

________ the office, Ifound the naughty boy _________ beside my desk, trembling.