Parents should see to it _______ their children form the habit of brushing their teeth every day.
A．this B．that C．whether D．if
The computer system _______suddenly while he was searching for information on the Internet.
A．broke out B．broke up C．broke in D．broke down
What fun it is to walk alone with full moon hanging in the sky.
A．/; a B．a; / C．the; / D．a ;the
With the victory at the French Open, Li Na has reached NO．4 in the world,______ the previous Asian record．
A．equaled B．equaling
C．to have equaled D．having equaled
I'm sorry you ______ so long, but it' ll still be some time before Jim gets back．
A．wait B．waited C．had waited D．have been waiting
