- What do you usually do at weekends?-I often practice ____English. A. speak B. to speak C. speaking
--- Lily is ill in hospital .---Really ? I _____ know she was ill .
The task is so hard for e . I don’t know _______________.
Good books help us ___________ a whole new world to me .
There is no air _______ water on the moon .
They don’t know what ___________ the problem .