During his stay in the USA, Yao Ming said that he would go back to China ______ he was needed.

We attend lectures in the school lecture hall atweekend ____ seats more than 800 students.

He never ________ no matter how many difficulties he has.

How soon will you come back from your hometown—_____ three weeks.

John, how did your English exam go? — I thought I ____, but in fact I came in the top 10% in the class.[ ]