20. _______, English is one of the most important subjects.
| A．It is known to all that | B．As is known to all that |
| C．As we know | D．As it is known to all |
. It is not I but you who ___ the first to run to the goal in the competition.
| A．was | B．were | C．are | D．is |
What he says and what he does ___ agree.
| A．doesn’t | B．don’t | C．isn’t | D．aren’t |
Although the first part is easy the rest ____.
| A．is supposed difficult | B．are difficult |
| C．has proved difficult | D．could have been difficult |
. Rain and freezing temperatures ____ to make snow.
| A．combined | B．combine | C．combine with | D．combined with |
. The express No.12_____ at two pm.
| A．reaches | B．gets in | C．cuts in | D．knocks |