--Do you mind if I smoke here?
--____________.
| A．Having caught | B．Be caught | C．Being caught | D．Caught |
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 |
We were about to leave the classroom _____ it began to rain.
| A．while | B．when | C．as | D．before |