单选题 Throughout history man has had to accept the fact that all living things must die, but people now live longer than they (51) Yet, all living things still show the (52) of aging, which will eventually (53) death.
Aging is not a disease, but as a person passes maturity, the cells of the body and the (54) they form do not function (55) they did in childhood and adolescence. The body provides less (56) against disease mad is more (57) accident.
A number of related causes may (58) aging. Some cells of the body have a fairly long life, but they are not (59) when they, die. As a person ages, (60) of brain cells and muscle cells decreases. (61) body cells die and are replaced by new cells. In an aging person the (62) cells may not be as viable or as (63) growth as those of a young person.
Another (64) in aging may be changes within the cells (65) Some of the protein chemicals in cells are known (66) with age and become less elastic. This is why the skin of old people (67) and hangs loose. This is also the reason old people (68) in height. There may be other more important chemical changes in the cells. Some complex cell chemicals, such as DNA and RNA, store and (69) information that the cells need. Aging may affect this (70) and change the information-carrying molecules so that they do not transmit the information as well.

单选题 A. use to B. be used to C. used to D. had
【正确答案】 C
【答案解析】be used to习惯于；used to过去，常常。
单选题 A. Sign B. effect C. fact D. symbol
【正确答案】 A
【答案解析】sign迹象，征兆；effect结果，效果；fact事实，实情；symbol象征，符号，标记。
单选题 A. stem from B. yield in C. originate from D. result in
【正确答案】 D
【答案解析】result in引起，导致；stem from来源于，源自；originate from发源于。
单选题 A. brains B. brain C. heart D. organs
【正确答案】 D
【答案解析】the organs they form它们所组成的器官。
单选题 A. as the past as B. as the same as C. as well as D. so long as
【正确答案】 C
【答案解析】句意：不如童年时代和青年时代运行得好。
单选题 A. resistance B. protection. C. energy D. alertness
【正确答案】 A
【答案解析】resistance抵抗力；protection保护，抵御；alertness警戒，机敏。
单选题 A. inclined to B. tended for C. bent against D. apt at
【正确答案】 A
【答案解析】(be)inclined to倾向于，易于；(be)tended for搭配不当；apt at聪明的，敏捷的。
单选题 A. concern with B. contribute to C. reduce to D. bring out
【正确答案】 B
【答案解析】concern with担心，关心；contribute to起促进作用；reduce to使陷于不利状况；bring out发挥，显示出。
单选题 A. replaced B. reborn C. recovered D. recuperated
【正确答案】 B
【答案解析】句意：细胞死亡后不能再生。reborn再生；replace替代，取代；recover复原；recuperate复原，恢复。
单选题 A. a number B. an amount C. tile number D. most
【正确答案】 C
【答案解析】句意：随着年龄的增长，脑细胞和肌肉细胞的数量在减少。
单选题 A. Some old B. Old C. The other D. Other
【正确答案】 D
【答案解析】句意：其他身体细胞死亡后被新细胞取代。
单选题 A. old B. remaining C. new D. replaced
【正确答案】 C
【答案解析】前面提到了与新细胞代替，紧接着讲新细胞在aging people身上的运行状况。
单选题 A. competent to B. qualified to C. capable of D. helpful in
【正确答案】 C
【答案解析】capable of有力量的，有能力的；competent to胜任的，称职的；qualified to具有……资格。
单选题 A. factor B. cause C. reason D. element
【正确答案】 B
【答案解析】上一段讲到a number of related causes，本处接着讲另一种诱因。
单选题 A. for themselves B. in themselves C. themselves D. of their own
【正确答案】 C
【答案解析】细胞自身的变化。
单选题 A. to reduce B. to decrease C. to change D. to decline
【正确答案】 B
【答案解析】decrease数量上减少；reduce降低，缩小；decline衰退，衰弱。
单选题 A. wrinkles B. rumples C. crinkles D. shrinks
【正确答案】 A
【答案解析】wrinkle(皮肤)起皱纹，皱起来；rumple把……弄乱，把……弄皱；crinkle使布或纸起皱；shrink收缩，缩短。
单选题 A. shorten B. shrink C. fatten D. decrease
【正确答案】 B
【答案解析】句意：这也是老年人身高减缩的原因。
单选题 A. transfer out B. give off C. send off D. pass on
【正确答案】 D
【答案解析】transfer out搭配不当；give off散发气味、液体等；send off寄、送信息等； pass on传给，传递。
单选题 A. mode B. procedure C. order D. process
【正确答案】 D
【答案解析】句意；衰老可能会影响这一过程。process过程，进程；procedure程序。