People have invented a lot in ________ century.

[　　]

A. twenty　　　　 　　B. twentieth

C. the twentieth　　　D. the twenty

As so many cars were held ________, we had to get off and walk.

[　　]

A. at　　　B. out　　　C. up　　　D. on

With plastics ________ to water we can use it to make raincoats.

[　　]

A. are resistant　　　B. is resistent

C. resistent　　　　　D. resistant

Articles made of plastics ________ expensive.

[　　]

A. not usually are　　　B. are usually not

C. usually are not　　　D. aren't usually

________ the three coats the leather one is ________ expensive.

[　　]

A. Of ... most　　　　　　　B. Of ... more

C. Among ... the most　　 　D. Among ... the more

Now he goes to school by bike instead of ________.

[　　]

A. on foot　　　　　B. going on foot

C. using feet　　　 D. walking

As he always eats more than he needs, he becomes ________.

[　　]

A. more and more weighty　　　　B. more and more weigh

C. weightier and weightier　　　D. weightyer and weightyer

I'm the only one of the teachers in our school who ________ able to speak German.

[　　]

A. are　　　B. is　　　C. am　　　D. was

________ in that key school work very hard at their lessons.

[　　]

A. Most of students　　　　　B. The most students

C. Most of the students　　　D. Most the students

________ are being manufactured in their factory.

[　　]

A. Bikes of different colour

B. The bikes of different colours

C. Bikes of different colours

D. The bikes of different colour