—Will you give me a hand? I have some trouble_______ the scientific problem.—Don't worry. I'll try my best to help you _______.
--Simon , I hear you are going abroad for further study. Have you decided ___ ?--Next September .
Everybody except the two young boys __________ shocked by the bad news. People looked at each other in __________.
After you finish the exercises, you’d better have your answers ___________.
It was getting dark, but the little boy didn’t know______________.
I don’t doubt ____________ she can do it well, but I doubt _________ she is willing to do it.