.On April Fool’s Day people often play tricks _____ others.

 The old man put his oars （船桨）in the water and _______ the smooth surface of the lake.

____people in the world are sending information by E-mail every day. 

Your niece is very strict and ______ worth teaching, but your nephew is not. Look, he is now ______ asleep in class.

The English spoken in the United States is only slightly different from ______ spoken in England.