--I don't think you can manage it. ----That ____!
—We didn't find the Blacks ________ the lecture. —No one had told him about ________ a lecture the following day.
Only ________ according to the directions can the medicine be quite effective.
The man we followed suddenly stopped and looked as if ________ whether he was going in the right direction.
—Hi,Mary.Would you like to go to the concert this evening? —Sorry,Tom.________ tomorrow's lessons,I have no time to go out with you.
Every student in our class had an application form in his hand,but no one knew which office ________.