Rewrite sentences, using the provided word keep meaning as that of the roof one. 1) Knowing English is very useful. 2) It started to snow at 5 o'clock. 3) Nam is taller than Hung. 4) When did you go to bed last night?

Rewrite sentences, using the provided word keep meaning as that of the roof one. 
1. Knowing English is very useful 
--> It....
2. It started to snow at 5 o'clock 
--> It ....
3. Nam is taller than Hung 
--> Hung....
4. When did you go to bed last night? 
--> What....
5. What time does Nam have to leave? 
--> Do you know....
6. He can not dance 
--> He wishes....
7. This book is very boring to me 
--> I am very....
8. Will be necessary for me to sleep under a net? 
--> Shall I have to....
9. An began to be interested in healthy eating 3 year ago 
--> An has been.....