一、单项选择题。

1.The old concerns lose importance and some of them vanish altogether.

A. develop

B. disappear

C. linger

D. renew

2.In the United States educational system, intermediate school is the transitional phase between the primary grades and high school.

A. stage

B. notion

C. pattern

D. alternative

3.Fluoride deters tooth decay by reducing the growth of bacteria that destroy tooth enamel.

A. facilitates

B. overwhelms

C. inhibits

D. loosens

4.The firm of Bonnin and Morris in Philadelphia was probably the first American company to manufacture porcelain.

A. silverware

B. crystal

C. china

D. linen

5.Gunpowder was used extensively in firearms prior to 1890.

A. in

B. around

C. from

D. before

6.We packed up the things I had accumulated over the last years and left for good.

A. close

B. near

C. past

D. final

7.The chemical is lethal to rats but safe to cattle.

A. toxic

B. harmful

C. deadly

D. contagious

8.She is very conscientious about her work.

A. worried

B. careful

C. anxious

D. nervous

9.She has consolidated her power.

A. strengthened

B. won

C. hardened

D. united

10.The drinking water is contaminated with impurities.

A. blackened

B. polluted

C. darkened

D. mixed

11.Her novel depicts a futuristic America.

A. writes

B. sketches

C. describes

D. indicates

12.He expressed concern that the ship might be in distress.

A. despair

B. difficulties

C. need

D. danger

13.They are endeavoring to change society as a whole.

A. trying

B. working

C. doing

D. making

14.Your eternal boasting annoys everyone.

A. unchangeable

B. everlasting

C. boring

D. monotonous

15.The other women seemed contented and they even exhibited their bellies with pride.

A. demonstrated

B. uncovered

C. spread

D. showed