Jenny is on holiday now. I wonder ______________________.
| A．when she will come back | B．when she came back |
| C．when will she come back | D．when did she come back |
It takes my mother one hour ______ to work
A. go B. to go C. going
I often go to school ______.
A. by bus B. by buses C. by a bus
It’s important _______ us __________English well.
A. of, learning B. for, to learn C. of, to learn
I spent three hours_____ this book.
A. finish reading
B. to finish reading
C. finishing reading
——What are you doing _______ vacation?
A. to B. for C. at