6.　　　 Water is a liquid at room temperature and a ____________ (相对地，比较而言地) high freezing point.

5.　　　 Because water is polar, it can break down both __________ (固体) and gases.

4.　　　 The water molecule is made up of two _____________ (氢) atoms and one ___________ (氧) atom.

3.　　　 Life in the oceans ranges from the tiniest ___________ (浮游生物) all the way up to giants like sharks and whales.

2.　　　 ___________ (河口) are great places for nature’s young ones.

1.　　　 The other _________ (海员；水手) are frightened and angry because the bird is thought to bring good luck to the ship.

25. More and more students are _______ this modern type of instruction.

A. benefiting from　　　　 B. comparing to　　　 C. giving off　　　 D. setting out

Class ______　 Name ____________　 No. _______　 Score: _______

24. ---- Must I finish the work before Saturday?

　 ---- No, you ________.

A. don’t need　　　 B. don’t have to　　　　 C. mustn’t　　　 D. can’t

23. ---- May I pick a flower in the garden?

----- _____.

A. No, you needn’t　　　　　　　　 B. Not, please

　 C. No, you mustn’t　　　　　　　　 D. No, you won’t

22. We ______ set out before seven tomorrow morning, or we shall miss the train.

A. can　　　　 B. may　　　　 C. would　　　　 D. had better