-_______do you spare time to visit your parents every month?
-Twice.
| A．How long | B．How often | C．How soon | D．How fast |
“Is there _____ here?” “No, Bob and Tim have asked for leave.”
| A．anybody | B．everybody | C．somebody | D． nobody |
I'll come to see you if _____.
| A．you're convenient | B．it is convenient for you |
| C．you feel convenient | D．it is convenient with you |
—Must I turn off the gas after cooking ?
—Of course . You can never be _______ careful with
that.
| A．enough | B．too | C．so | D．very |
_____ is known to everybody, the moon travels round the earth once every month.
| A．It | B．As | C．That | D．What |
It is so difficult a problem that _____ student in this class _____ work it out.
| A．any, can't | B．no, can | C．every, can | D．no, can't |