Viết lại câu : George knew how to ride a bicycle when he was five

1. George knew how to ride a bicycle when he was five
=> George was
2. I wanted to go to the party, but it was snowing hard.
=> I couldn't
3. Isn't it high time you greased the hinges? (need)
=>
4. It isn't necessary to feed the cats. I've already fed them.(have)
=> You.......................................................the cats.
5. It's prohibited to take pets into the museum.(not)
=>You..........................................................into the museum.
6. It isn't necessary to change the sheets. I'll do it tomorrow.(need)
=> You...........................................................the sheets
7.Students aren't allowed to leave the dormitory after 11p.m(not)
=>Students ..........................................................after 11p.m
8. Kindergarden students needn't wear school uniform. (have)
=>Kindergarden students.........................................................school uniform