In recent years, many mainland residents have rushed to Hong Kong to buy baby milk powder due to their ________ about its quality.
He said ______ couldn’t he work out the problem but his teacher didn’t know how to do it.
The problem ______ many children,especially girls,have ______ school is getting more and more serious.
Usually children are allowed to ______ when they are six years old.
–Did you take enough money with you? –No, I needed _______ I thought I would.
–What did your parents think about your decision?–They always let me do _______ I think I should.