Though they had not much to say, they email each other _____ .
| A．sooner or later | B．from then on | C．every now and then | D．more or less |
People say it is Canada’s most beautiful city, _____ by mountains and the Pacific Ocean.
| A．surrounding | B．surround | C．to surround | D．surrounded |
The thought _____ they could cross the whole continent was exciting.
| A．that | B．what | C．which | D．why |
We watched, amazed as fire _____ on the outside of the spaceship as the earth’s gravity increased.
| A．broke up | B．broke out | C．broke in | D．broke away |
Walking does need a bit of practice _____ gravity has changed.
| A．as if | B．in their turn | C．now that | D．as a result of |
They multiplied and filled the oceans and seas with oxygen, _____ encouraged the later development of early shellfish and all sorts of fish.
| A．that | B．where | C．when | D．which |