单选题
Vitamins are organic compounds necessary in small amounts in the diet for the normal growth and maintenance of life of animals, including man.
They do not provide energy,{{U}} (31) {{/U}}do they construct or build any part of the body. They are needed for{{U}} (32) {{/U}}foods into energy and body maintenance. There are thirteen or more of them, and if{{U}} (33) {{/U}}is missing a deficiency disease becomes{{U}} (34) {{/U}}.
Vitamins are similar because they are made of the same elements -- usually carbon, hydrogen, oxygen, and{{U}} (35) {{/U}}nitrogen. They are different{{U}} (36) {{/U}}their elements are arranged differently, and each vitamin{{U}} (37) {{/U}}one or more specific functions in the body.{{U}} (38) {{/U}}enough vitamins is essential to life, although the body has no nutritional use for{{U}} (39) {{/U}}vitamins. Many people,{{U}} (40) {{/U}}, believe in being on the "safe side" and thus take extra vitamins. However, a well-balanced diet will usually meet all the body's vitamin needs.
【正确答案】 C
【答案解析】[解析] 空白后的句子主谓颠倒，所以空白处只能选C。
【正确答案】 D
【答案解析】[解析] transforming“改变，转变”，与后面的介词into搭配。
【正确答案】 A
【答案解析】[解析] any“任何一种”，这儿指“any vitamin”，谓语动词用单数is。
【正确答案】 B
【答案解析】[解析] apparent意为“明显的，显而易见的”。其余三个词意思都不对。
【正确答案】 C
【答案解析】[解析] sometimes意为“有时”，与前面的usually相对照。
【正确答案】 A
【答案解析】[解析] in that意为“因为，在于”，引导表示原因的状语从句。
【正确答案】 D
【答案解析】[解析] performs意为“执行，履行，完成”，可与functions搭配，其余三个词都与之不搭配。
【正确答案】 B
【答案解析】[解析] Getting在这儿作“吸收”解，可与vitamins搭配。其余三个词都与之不搭配。
【正确答案】 C
【答案解析】[解析] excess意为“过量的，过多的”。上段讲了vitamin的用途，这儿讲太多的 vitamin也没用，意思前后照应。
【正确答案】 A
【答案解析】[解析] A. nevertheless“然而，可是”，表示转折语气。B．therefore“因此”，表示因果关系；C. moreover“此外”，表示递进关系；D．meanwhile“同时”。