With an online course Lynn has over 300, 000 students all over China ________her class through the Internet．
A．are attending B．attended C．attend D．attending
There is a real danger ______ the U．S will not keep its position on the world economic stage．
A．where B．that C．which D．one
The trees in that thick forest are so close together that there is hardly any room to move _______them．
A．between B．in C．among D．across
Please keep ______ secret that he has decided to give up his present position．
A．one B．this C．it D．that
---Helen, will you be at the party tonight?
---Yes, but I really_________ as I have so much homework to do．
A．can’t B．shouldn’t C．mustn’t D．won’t
—Excuse me, I wonder if you can help．I ______ my ID card．
—But where did you lose it?
A．have lost B．lost C．had lost D．lose
