The plastic bottle, __________top cut off, is used to grow a flower in.

_Why is John so poor at his lessons _Henever studies ，heplays computer games all day

What impressed me most was that they never ______ in face of so many difficulties.

I knocked on the door several times but answered,so I left.

Where has all the time gone I can still remember the day when I first came to this school, but now I am about to leave.-_______.