【题目】We ______ Thanksgiving since the first pioneers arrived in America.

【题目】No shouting, please! It is ______ the rules in the museum.

【题目】You have to leave now ______ you can get to the classroom on time.

【题目】Deng Yaping helped make the Beijing Olympics a victory for world sport. She is ______ the best.

【题目】I like physics best, because I can do a lot of ______.

【题目】One day in 1939, Norman Bethune cut his finger during ______ operation.

【题目】I ______ the book to him if he ______ here next Sunday.

【题目】Don’t worry about me. I will call you ______ I arrive in London.

【题目】Tina managed ______ the train ticket to go home.

【题目】You ________open the door before the car stop. It's dangerous.