As more and more cars are produced and used, so the _____ from their exhaust-pipes contains an even larger volume of poisonous gas.
| A．exposure | B．distribution | C．expansion | D．emission |
The scientists recommend that studies ________ to find out what side effects the medicine might cause.
| A．be done | B．should do |
| C．will be done | D．are done |
An advertisement is useful in ________ it lets customers know of the kinds of goods in the shops.
| A．that | B．which | C．what | D．whether |
—I need some fresh air, so I am going out for a walk.
—________.
| A．You'd better not | B．Have fun |
| C．With pleasure | D．I sure am |
—Don't you know that a proper amount of exercise a day will ________ to a person's health?
—No wonder so many senior citizens do exercise in the square.
| A．construct | B．conclude |
| C．distribute | D．contribute |
The home ________ the lion is Africa while the koala bear is native ________Australia.
| A．of；of | B．to；to |
| C．of；to | D．to；of |