－What do you think of the book?
－Oh, excellent. It’s worth ______ a second time.
| A．to read | B．to be read | C．reading | D．being reading |
.Mathematics ______ the language of science.
| A．is | B．has been | C．are | D．have been |
.The young ______ the vital forces in our society.
| A．is | B．has been | C．are | D．have been |
.Every man, woman and child ______ some history, enough at least, to survive in the world.
| A．knows | B．know | C．is known | D．are known |
.None of them ______ my friends.
| A．is | B．are | C．was | D．has been |
.Not only the whole nation, but the whole Europe , indeed the whole human society ______ to alter its attitude to racial problems.
| A．need | B．needs | C．has a need | D．have a need |