With his son _____, the old man felt unhappy.
| A．to disappoint | B．to be disappointed | C．disappointing | D．being disappointed |
I ________ thank you too much for all your help to my son while we were away from home.
| A．won’t | B．can | C．can’t | D．will |
. I'd really appreciate ________ if you would turn off the lights before you leave.
| A．you | B．that | C．as | D．it |
It never _____ humans until the mid1990s that some animals can be cloned.
| A．occur | B．is occurred | C．occurred to | D．occurred |
If you _____ his wife’s income____ his own，the total of their income _____ 3000 yuan.
| A．add; to; will add up to | B．add; to; adds to |
| C．add up; to; adds up to | D．will add; for; adds up |
Is it a wonder that ____little cells can store much energy?
| A．so; so | B．so; such | C．such; such | D．such; so |