It was ________ who respected their teachers.

下列词语中字形全都正确的一项是（ ）

I’ll spend as much time as I can ____ after the flowers in the garden.

I can hardly work out the answer _____ thisdifficult question.

Did you hear that Tonna took social management as her major?—Yes,but she shouldn’t have,you see.This kind of subject ________one’s communication ability,and that’s what she is most weak at.