动词填空 用括号内所给动词的适当形式填空，并将答案写在答题卡标有题号的横线处（本大题共8小题，每小题1分，共8分）
You mustn’t enter the room unless you _____________ (allow) to.
More effort should be put into _____________ (protect) our environment.
His parents promised that they ____________ (take) him to the USA if he did well in all his subjects.
— Hi, Lin Tao. I didn’t see you at the party.
— Oh. I __________ (get) ready for the math exam.
The sign on the wall says people are against__________ (smoke) in public places.
— Why didn’t you give the wallet back to the man at once?
— He __________ (disappear) before I realized it was his.
It is a little difficult to guess the exact dates when iPad 6__________ (hit) the market.
— It seems that you know a lot about the story.
— Well. We _____________ (read) it many times.