China's high﹣speed railways _____ from 9，000 to 29，000 kilometres in the past few years．（ ）
A．are growingB．were growing
C．will growD．have grown
She is listening to music he is doing his homework．（ ）
A．afterB．beforeC．while
He is at English than me．（ ）
A．goodB．betterC．best
It's our duty our hometown clean and beautiful．We must do something for it．（ ）
A．keepingB．keepsC．to keep
I have friends，so I feel sad．（ ）
A．fewB．a fewC．little
Jim sits behind me，so I sit him．（ ）
| A． |
at the end of |
B． |
in front of |
C． |
in the middle of |