The poor boy couldn't work the problem out. He wasn't ____ clever.

--How ___ do you go to the cinema?---Once a week.

Mother is glad that he’s already done_______ 60% of the work in such a short time.(西安市)

Trees are good for human being. We can’t plant them __________ many.

I was wondering what to do and＿＿＿＿＿＿Mr. Wang came in.