Some people get in touch with each other by mobile phones__________ others keep contact with each other by e-mail.
| A．when | B．before | C．while | D．since |
Thomas Alva Edison was __________ American inventor and __________ businessman who developed many devices, such as __________ bulb, that greatly influence life worldwide.
| A．the; a; the | B．an; a; / |
| C．an; /；the | D．an; the; / |
I am quite __________ that the new cosmetics, whether it appears in the form of tablet, capsule, powder or injection, will __________ through the country among young ladies.
| A．optimistic about; sweep | B．optimistic; sweep |
| C．pessimistic; spread | D．pessimistic about; spread |
The situation is getting worse. We must ________ the trouble __________.
| A．keep; spreading | B．prevent; spreading |
| C．stop; to spread | D．protect; to spread |
Under no conditions __________ his home turned into a battlefield between the forces of light and darkness.
| A．would he have | B．he would have |
| C．would have he | D．he would have had |
On no condition __________ practice makes perfect.
| A．we should forget | B．forget we |
| C．shouldn't we forget | D．should we forget |