Cars play an important role in modern life, but they_______also cause many problems like air pollution．
| A．should | B．can | C．must | D．will |
Mary wrote an article on ____the team had failed to win the game .
| A．why | B．what | C．who | D．that |
After Yang Liwei succeeded in circling the earth ,_______our astronauts desire to do is walk in space .
| A．where | B．what | C．that | D．How |
we can not figure out ____quit a number of insects ,birds ,and animals are dying out .
| A．that | B．as | C．why | D．when |
He was chosen _________ of the company.
| A．manager | B．a manager | C．the manager | D．as a manager |
In the botanic garden we can find a（n）______of plants that range from tall trees to small flowers.
A．spec ies |
B．group | C．amount | D．variety |