2009届高考英语二轮复习完形填空试题库(4)

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will eventually death.

Aging is not a disease, but as a person passes maturity (成熟期), the cells of the body and the in childhood and teenage years. The body provides less against disease and is more to have accident.

A number of related causes may aging. Some cells of the body have a fairly long life, but they are not when they die. As a person ages, of brain cells and muscle cells decreases. body cells die and are replaced by new cells. In an aging person the cells may not be as workable or as capable growth as those of a young person.

Another in aging may be changes within the cells . Some of the protein chemicals in cells are known with age and become less elastic (有弹性的). This is why the skin of old people wrinkles (皱纹) and . This is also the reason why old people in height. There may be other more important chemical changes in the cells. Some complex cell chemicals, such as DNA and RNA, store and information that the cells need． Aging may affect this and change the information-carrying molecules so that they do not transmit the information as well.

36. A．would

B．be used to

C．used to

D． used D． sign D． result in D． organs D． had done D． power D． alike D． devote to D． surrendered D． a great deal D． Other D． other D． in D． element

37. A．function B．effect C．affect 38. A．lead in B．give in 39. A．hands B．feet 40. A．do B．has done 41. A．energy B．protection 42. A．likely B．probable

C．run into C．heart C．did C．vigor C．possible

43. A．attend to B．contribute to C．add to 44. A．replaced B．reborn 45. A．a number B．the amount

C．recovered C．the number

46. A．The others B．The other C．Another 47. A．old B．left 48. A．to

B．for

C．new C．of C．reason

49. A．factor B．effect

50. A．for themselves B．of themselves C．themselves D． on their own