---I think English is ____unimportant subject.---I don’t think so. It is ____useful tool when we talk with foreigners.
I can do many kinds of housework _______ cooking. I’ll learn it from my mother.
I think _______ necessary for you _______ breakfast.
—Wang Yi plays basketball so well! Who taught _______? —He learnt it by _______.
—I have a toothache. —You should _______.
---Where is your tape player? ---___________________.