Jane likes collecting stamps very much.In fact,her interest in it________her school days.[ ]

一Oh, poor Peter looks very weak.一＿if you suffer from a high fever for three days on end.

None of the shoes in the shops are the right size. They are _____too big ____too small.

She’s aiming ________ a scholarship. That is why shehas been focusing her mind ________ her work.

下列各句中，加横线的成语使用恰当的一句是（ ）