1.The school guard often leads young children ... their classroom.
2.The little boy got up because the alarm went........ 3.Are you satisfied. your new job?
4. These students often chat............their study.
5. the train arrives.........the station.........7 a.m every day.
6. I gave.. .my weekend to help him paint his apartment.
7. The plane was flying.. .bad weather. 8.Our environment is ..danger. pollution. 9. The room was crowded. foreign visitors. 10. many people screamed. panic.