The boys when the teacher came in. So she was very angry．
| A．were doing homework |
| B．were cleaning the classroom |
| C．were fighting |
| D．were learning English |
--- We'll visit the Summer Palace_______ there is a heavy rain tomorrow.
--- OK ! Boating on the lake must be interesting.
| A．unless | B．since | C．until | D．if |
You can try_______ second time if you fail_______ first time.
| A．the; the | B．a; the | C．the; a | D．a; a |
— I visited the Purple Mountain Observatory last Sunday.
—______ Why didn’t you tell me earlier?
| A．You did? | B．I hope so. |
| C．Have a good time! | D．It’s so kind of you. |
—What is your mother going to do this Saturday?
—I’m not sure. She ______ go to see my grandmother.
| A．can | B．may | C．must | D．should |
The kind lady devoted all her life ______ those homeless children.
| A．helped | B．helping | C．to help | D．to helping |