问题 选择题
如图所示为一磁流体发电机示意图,A、B是平行正对的金属板,等离子体(电离的气体,由自由电子和阳离子构成,整体呈电中性)从左侧进入,在t时间内有n个自由电子落在B板上,则关于R中的电流大小及方向判断正确的是(  )

A.I= ,从上向下

B.I= ,从上向下

C.I= ,从下向上

D.I= ,从下向上

答案

答案:A

阅读理解

I have been consistently opposed to feeding a baby regularly. As a doctor, mother and scientist in child development I believe there is nothing to recommend it, from the baby’s point of view.

Mothers, doctors and nurse alike have no idea of where a baby’s blood sugar level lies. All we know is that a low level is harmful to brain development and makes a baby easily annoyed. In this state, the baby is difficult to calm down and sleep is impossible. The baby asks for attention by crying and searching for food with its mouth.

It is not just unkind but also dangerous to say a four-hourly feeding schedule will make a baby satisfied. The first of the experts to advocate a strict clock-watching schedule was Dr Frederic Truby King who was against feeding in the night. I’ve never heard anything so ridiculous. Baby feeding shouldn’t follow a timetable set by the mum. What is important is feeding a baby in the best way, though it may cause some inconvenience in the first few weeks.

Well, at last we have copper-bottomed research that supports demand feeding and points out the weaknesses of strictly timed feeding. The research finds out that babies who are fed on demand do better at school at age 5, 7, 11 and 14, than babies fed according to the clock. By the age of 8, their IQ (智商)scores are four to five percent higher than babies fed by a rigid timetable. This research comes from Oxford and Essex University using a sample (样本)of 10,419 children born in the early 1990s,taking account of parental education, family income, a child’s sex and age, the mother’s health and feeling style. These results don’t surprise me. Feeling according to schedule runs the risk of harming the rapidly growing brain by taking no account of sinking blood sugar levels.

I hope this research will put an end to advocating strictly timed baby feeling practices.

小题1:According to Paragraph 2, one reason why a baby cries is that it feels______.

A.sick

B.upset

C.sleepy

D.hungry小题2:What does the author think about Dr King?

A.He is strict

B.He is unkind

C.He has the wrong idea

D.He sets a timetable for mothers小题3:The word copper-bottomed in Paragraph 4 is closest in meaning to _________.

A.basic

B.reliable

C.surprising

D.interesting小题4:What does the research tell us about feeling a baby on demand?

A.The baby will sleep well

B.The baby will have its brain harmed

C.The baby will have a low blood sugar level

D.The baby will grow to be wiser by the age of 8小题5:The author supports feeling the baby_______.

A.in the night

B.every four hours

C.whenever it wants food

D.according to its blood sugar level

单项选择题