1. The students are listening ___   their teacher very carefully.
2.——I'm looking forward ____ taking a holiday in Hainan. 
   ——So am I.It's great to be ____ holiday there.
3. Sichuan is one of the largest provinces ____ China.  It's ____ the southwest ____ China.
4.——It's necessary ____ you to take exercise ____ the morning.  
   ——I agree ____ you. It's very kind ____ you to give me advice.
5. The moonlight comes in ____ the window and the room seems quiet and peaceful.