Some house plants grow better if placed near a window with plenty of sunlight ______ others prefer to be in a more shaded spot.
| A．unless | B．since | C．when | D．while |
— Will you go to the World Expo in Shanghai by bullet train after the Examination?
—_______ I may go by air.
| A．Why not? | B．Not really. | C．How come? | D．Oh, great. |
There are two main sets of Games — the Winter and the Summer Olympics, and both are held every four years on a _________ basis.
| A．valuable | B．former | C．regular | D．swift |
The __________ to the rocket going into space went wrong, and as a result it exploded and fell into the sea.
| A．mark | B．sign | C．symbol | D．signal |
Put the cleaned fish in a mixture of 300g of salt and one liter of water to ________ all of the blood from the fish meat.
| A．replace | B．remove | C．calculate | D．spoil |
We give dogs time, space and love we can spare, and ____________, dogs give us their all.
| A．in charge | B．in fact | C．in case | D．in return |