As a teacher, I seldom give my students so difficult a problem ________ they can not work out.
| A．that | B．if | C．in order that | D．as |
The place the bridge is supposed to be built should be the cross-river traffic is the heaviest.
| A．which; where |
| B．at which; which |
| C．at which; where |
| D．which; in which |
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 desired to do was walking in space.
A. where
B. what
C．that
D，how
We can not figure out quite a number of insects, birds, and animals are dying out.
| A．that |
| B．as |
| C．why |
| D．when |
The road is covered with snow. I can’t understand they insist on going by motorbikes.
| A．why |
| B．whether |
| C．when： |
| D．how |