Whenever I met her，________ was fairly often, she greeted me with a sweet smile.
| A．who | B．which | C．when | D．that |
Large quantities of china made in Dehua __________ to the US and Europe.
| A．has exported |
| B．will export |
| C．is exported |
| D．are exported |
-It's said that scientists have made __________ big breakthrough in the cancer treatment.
-If so, many people can have been brought back to __________ life ！
| A．a; / |
| B．/；a |
| C．the; the |
| D．a; the |
The police __________ searching for the murderer everywhere when he suddenly appeared in a theatre.
| A．is |
| B．was |
| C．are |
| D．were |
Experiments of this kind __________ in both the U. S. and Europe well before the Second World War started.
| A．have conducted |
| B．have been conducted |
| C．had conducted |
| D．had been conducted |
After the explosion, every means __________ prevent the river from __________.
| A．is used to; polluting |
| B．are used to; polluting |
| C．has been used to; being polluted |
| D．are used to; being polluted |