－Why did you arrive late?(成都市)－The fog_______ our air flight for about half an hour.

_____ teens are using the Internet for both social and intellectual development, they are also facing significant challenges on how to manage their relationships online.

1— _______ is your father— He’s 43.

_____ Jack ______ Jim has been to China, but _____ of them knows much about China in fact.

Yao Ming is a popular basketball player____ the Chinesepeople.