Don't forget ______ the light when you leave the office.
| A．switching over | B．to turn on |
| C．to switch on | D．to switch off |
Old McDonald gave up smoking for a while, but soon _____ to his old way.
| A．returned | B．returns |
| C．was returning | D．had returned |
What _____ to Joan last night? What did she cry for?
| A．was happened | B．happened |
| C．was happening | D．had happened |
_____ is the population of your country?
| A．How | B．what | C．How many | D．How many |
Please say "Hi" to Bob ______ me.
| A．to | B．for | C．about | D．from |
After we walked ______ the forest, and ______ a river, we arrived at that small village.
| A．across; across | B．through; across |
| C．across; through | D．through; through |