---Is Johnson on duty today?
---It ________ be him, but I’m not sure.
| A．will | B．may |
| C．need | D．must |
You can imagine what difficulty we had __________ home in the snowstorm.
| A．walked | B．walking | C．to walk | D．walk |
We hurried to the station, ________ the train was gone.
| A．to find | B．finding | C．found | D．only to find |
Operation rooms should be kept free ______ bacteria of any kind.
| A．with | B．for | C．from | D．to |
The League Secretary and monitor ______giving a speech while the rest of the class ________ listening attentively.
| A．were, were | B．was, was | C．were, was | D．was, were |
Mr. Wang is a man of _________ and we have got much _________ from him about how to make a living.
| A．experience; experiences | B．an experience; an experience |
| C．experiences; experience | D．experiences; experiences |