It was several years later________ an American ship paid the first official visit to the island.
| A．since | B．when | C．that | D．as |
The purpose of the campaign is to raise the public’s_______ of the dangers of passive smoking.
| A．existence | B．connection | C．awareness | D．consciousness |
A recent study has come up with _____ unexpected conclusion that ____ Africa elephants should be divided into two different species.
| A．a, the | B．an, the | C．an, an | D．the, the |
On Halloween, children in American like to _____ as ghosts to frighten people.
| A．dress up | B．put on | C．make up | D．spy on |
No one but the experts in this field can _____ the difference between them.
| A．recognize | B．speak | C．spot | D．predict |
At first, we didn't know about Tom. But ____, we came to know that he was an honest boy.
| A．suddenly | B．luckily | C．gradually | D．slightly |