问题 单项选择题

有关甲状腺素的说法正确的是

A.甲状腺素分四碘甲状腺原氨酸(T4)和三碘甲状腺原氨酸(T3)两种

B.释放入血的甲状腺素与体内甲状腺球蛋白结合

C.甲状腺中90%为T3,10%为T4

D.甲状腺素促进碳水化合物和脂肪分解,促进蛋白质合成

E.甲状腺素作用于垂体细胞,通过负反馈机制抑制生长激素分泌

答案

参考答案:A

选择题
单项选择题

Personality is to a large extent inherent. A-type parents usually (1) A-type offspring. But the environment must also have a profound effect (2) if competition is important to the parents, it is (3) to become a major factor in the lives of their children.

One place where children (4) A characteristics is school, which is, (5) its very nature, a highly competitive institution. Too many schools (6) the "win at all costs" moral standard and measure their success by sporting achievements. The current (7) for making children compete against their classmates or against the (8) produces a two-layer system, in which competitive A types seem in some way better than their B type fellows. Being too (9) to win can have dangerous consequences: remember that Pheidippides, the first marathon runner, (10) dead seconds after saying. "Rejoice, we conquer!"

(11) the worst form of competition in schools is the disproportionate emphasis on examinations. There is, for example, a (12) school that allows pupils to concentrate on those things they do well. The (13) of competition by examination are somewhat questionable, but competition in the certain (14) of failure is positively harmful.

(15) , it is neither practical nor desirable that all A youngsters change into B’s. The world needs types, and schools have an important duty to try to (16) a child’s personality to his possible future employment. It is top management.

If the preoccupation of schools with academic work was (17) , more time might be spent teaching children surer values. Perhaps selection (18) the caring professions, especially medicine, could be made less by good grades in chemistry and more by such (19) as sensitivity and sympathy. It is surely a mistake to choose our doctors exclusively from A type stock. B’s are important and should be (20) .

1()

A. bring about

B. care for

C. carry on

D. keep up