为了减轻火花放电和感应带电的危险，可采用阻值为( )Ω的导电性工具。A．70～100

与卵细胞形成过程相比，精子形成过程特有的是[ ]

A．染色体数目减半

B．精细胞的变形

C．非同源染色体自由组合

D．同源染色体两两配对

拮抗维生素K，抑制维生素K在肝细胞合成凝血因子Ⅱ、Ⅶ、Ⅸ、Ⅹ，发挥抗凝血作用的抗凝血药是（）。

A.磺达肝葵钠

B.水蛭素

C.依诺肝素

D.阿哌沙班

E.双香豆素

我国《商业银行法》规定，银行工作人员不得在其他经济组织兼职。作为一家银行的部门总经理，孙某在当地企业家协会兼任顾问的行为( )。

A．与银行业务不直接相关，因此可以不披露自己的兼职兼作

B．非营利机构属允许范围内的兼职活动，并应当向所在银行披露自己的兼职身份

C．非营利机构属允许范围内的兼职活动，可以把一半以上的时间用于此兼职工作

D．违反了有关法律法规和职业操守的规定，必须停止兼职活动

委托加工收回的应税消费品尚未销售，由于受托方未代收代缴消费税，委托力+应看作自制应税消费品补交消费税。（）

Whether to teach young children a second language is disputed among teachers, researchers and pushy parents. On the one hand, acquiring a new tongue is said to be far easier when young. On the other, teachers complain that children whose parents speak a language at home that is different from the one used in the classroom sometimes struggle in their lessons and are slower to reach linguistic milestones. Would a 15-month-old child, they wonder, not be better off going to music classes

A study just published in the Proceedings of the National Academy of Sciences may help resolve this question by getting to the point of what is going on in a bilingual child’s brain, how a second language affects the way he thinks, and thus in what circumstances being bilingual may be helpful. Agnes Kovacs and Jacques Mehler at the International School for Advanced Studies in Trieste say that some aspects of the cognitive development of infants raised in a bilingual household must be undergoing acceleration in order to manage which of the two languages they are dealing with.

The aspect of cognition in question is part of what is termed the brain’s “executive function”. This allows people to organise, plan, prioritise activity, shift their attention from one thing to another and suppress habitual responses. Bilingualism is common in Trieste which, though Italian, is almost surrounded by Slovenia. So Dr. Kovacs and Dr. Mehler looked at 40 “preverbal” seven-month-olds, half raised in monolingual and half in bilingual households, and compared their performances in a task that needs control of executive function.

First, the babies were trained to expect the appearance of a puppet on a screen after they had heard a set of meaningless words invented by the researchers. Then the words, and the location of the puppet, were changed. When this was done, the babies who speak only one language had difficulty overcoming their learnt response, even when the researchers gave them further clues that a switch had taken place. The bilingual babies, however, found it far easier to switch their attention — counteracting the previously learnt, but no longer useful response.

Monitoring languages and .keeping them separate is part of the brain’s executive function, so these findings suggest that even before a child can speak, a bilingual environment may speed up that function’s development. Before rushing your offspring into bilingual kindergartens, though, there are a few cautions. For one thing, these extraordinary cognitive benefits have been demonstrated so far only in “crib” bilinguals — those living in households where two languages are spoken routinely. The researchers speculate that it might be the fact of having to learn two languages in the same setting that requires greater use of executive function. So whether those benefits apply to children who learn one language at home, and one at school, remains unclear.

How does a second language affect the way a young child behaves according to the new study（）

A. It shortens his focus time on anything learnt

B. It always switches his attention to new information

C. It makes him able to predict the appearance of a person

D. It makes him far easier to overcome his learnt response