第80節(2 / 3)

(C) while there is

(D) that there are

15. Almost ______ substances expand in volume when heated and contract when cooled.

(A) all

(B) they all

(C) all of

(D) all are

16. A children''s librarian often conducts story hours and other activities to help children

A B

enjoy herself while developing an interest in reading and the library''s resources.

C D

17. Titanium has the strength of steel but weighs half only as much, hence its advantage

A B C

for use in aircraft.

D

18. Protective behaviors of amphibians include hiding in the presence of danger and

A B

having coloration such closely matching the environment that the animal is not Obvious.

C D

19. As the highest-paid star of the silent screen, earning a reputedly income of $20, 000

A B C

a week, Gloria Swanson epitomized the glamour of Hollywood in the 1920''s.

D

20. Candles may be made by repeatedly dipping wicks in tallow, by molding, nor by

A B

pouring melted wax over the wicks and rolling them into shape.

C D

21. While models of automobiles date back as far as the late 1600''s, the 1880''s seen the

A B C

first commercial interest in the vehicle.

D

22. The conceptual of musical harmony is generally traced to the ninth century because it