问题 单项选择题

某人每年有应税收入23000美元,并且上缴8000美元收入税。后来此人每年的收入增加到30000美元,这使得他每年必须缴纳10000美元收入税。这种情况下的个人税收体系属于:

A.累进的。
B.累退的。
C.边际的。
D.比例的。

答案

参考答案:B

解析:
A.不正确,在累进税体系中,税金总额和收入中用来纳税的百分比(平均税率)都是随着收入增加而增加的。根据题目中的案例描述,这个人支付的税额更高了,但是税金占收入的百分比却下降了。
B.正确。这个人缴纳的平均税率从8000÷23000=34.8%下降到了10000÷30000=33.3%。在累退税体系中,尽管纳税总额可能上升,但平均税率随着收入的增加而降低。
C.不正确,因为“边际的”并不是一种税收体系类型,只是一种税率而已。边际税率就是收入增加量所付的税率。
D.不正确,在比例税体系中,平均税率和收入水平没有关系。本题中,这个人的平均税率是随着收入降低的。

单项选择题

Few scientific fields are as full of risk as that of research into human intelligence. The two questions that (1) over and over again are "is it a result of nature or nurture" and "does race make a difference"

Making (2) comments about the second question can be a (3) move, as James Watson, a co-discoverer of DNA structure, recently found. He suggested that he was " (4) about the prospect of Africa" (5) "all our social policies are based on the fact that their intelligence is the same as ours (white people) (6) all the testing says not really". Such (7) by Dr. Watson are not merely (8) , they are scientifically weird. If the term (9) has any useful scientific meaning, then Africa, the continent where modern humanity began, is most racially diverse. The resulting (10) among the public forced Dr. Watson to leave his laboratory.

(11) , the study of the first question (12) between intelligence and genetics— has some wiser practitioners. One of them, Terrie Moffitt, of King’s College, has just (13) a project judging the relative importance of nature and nurture. Dr. Moffitt’s team (14) the effect on intelligence of breastfeeding, but in a genetic context. Previous studies have shown that breastfed children are more intelligent, (15) about six IQ points, than those given baby formulas.

The team, however, (16) the involvement of a gene called FADS2, which comes in two varieties, known as C and G. The researchers (17) if these two varieties interacted differently with breast milk. (18) on data from two groups of people, they found that the intelligence increase associated with breastfeeding only happened to people having (19) at least one copy of the C variety. The effect did not. (20) on the social classes or IQs of the parents.

18()

A.Deciding

B.Acting

C.Drawing

D.Reflecting

单项选择题