He made another wonderful discovery, ______ of great importance to science.
| A．which I think it is | B．which I think is |
| C．which I think | D．I think which is |
The student was just about to_________ the question,when suddenly he found the answer.
| A．arrive at | B．work out |
| C．stick to | D．give up |
.I wish I_________ longer this morning,but I had to get up and come to class.
| A．could have slept | B．slept |
| C．might have slept | D．have slept |
We _________ our breakfast when an old man came to the door.
| A．just have had | B．have just had |
| C．just had | D．had just had |
_________with the size of the whole earth,the highest mountain does not seem high at all.
| A．When compared | B．Compare |
| C．While comparing | D．Comparing |
The bridge was named_________ the hero who gave his life for the cause of the people.
| A．after | B．with | C．by | D．from |