男性，33岁，体重70kg，矿工，瓦斯爆炸烧伤，面颈(头部除外)、双上肢、双下肢(臀

既阻断甲状腺激素生物合成，又能阻止周围组织中T4转化为T3的药物为

A．丙硫氧嘧啶
B．甲巯咪唑(他巴唑)
C．卡比马唑(甲亢平)
D．普萘洛尔(心得安)
E．大剂量¹³¹I

某单原子分子理想气体进行卡诺循环时，高温热源的温度为227℃，低温热源的温度为127℃，则该循环的效率为( )。

A．56%
B．34%
C．80%
D．20%

同步内隔一根立杆的两个相隔接头在高度方向错开的距离不宜小于（）mm。

A.200

B.300

C.400

D.500

This week marks the 10th anniversary of the Alar apple scare, in which many American consumers were driven into a panic following the release of a report by an environmental organization claiming that apples containing the chemical Alar posed a serious health threat to preschoolers. The report was disseminated through a PR (Problem Report) campaign and bypassed any legitimate form of scientific peer review. Introduced to the American public by CBS "60 Minutes", the unsubstantiated claims in the report led some school districts to remove apples from their school lunch programs and unduly frightened conscientious parents trying to develop good eating habits for their children.

Last month, Consumers Union released a report warning consumers of the perils of consuming many fruits and vegetables that frequently contained "unsafe" levels of pesticide residues. This was especially true for children, they claimed. Like its predecessor 10 years earlier, the Consumers Union report received no legitimate scientific peer review and the public’s first exposure to it was through news coverage.

Not only does such reporting potentially drive children for consuming healthful fruits and vegetables, the conclusions were based on a misleading interpretation of what constitutes a "safe" level of exposure. Briefly, the authors used values known as the "chronic reference doses", set by the U. S. environmental Protection Agency, as their barometers of safely. Used appropriately, these levels represent the maximum amount of pesticide that could be consumed daily for life without concern. For a 70-year lifetime, for example, consumers would have to ingest this average amount of pesticide every day for more than 25,000 days. It is clear, as the report points out, that there are days on which kids may be exposed to more; it is also clear that there are many more days when exposure is zero. Had the authors more appropriately calculated the cumulative exposures for which the safety standards are meant to apply, there would have been no risks and no warnings.

Parents should feel proud, rather than guilty, of providing fruits and vegetables for their children. It is well established that a diet rich in such foods decreases the risk of heart disease and cancer. Such benefits dramatically overwhelm the theoretical risks of tiny amounts of pesticides in food. So keep serving up the peaches, apples, squash, grapes and pears.

The "chronic reference doses" (in boldface in Paragraph 3) refer to ().

A. the safe levels of pesticide exposure

B. the amount of fruits one can safely eat

C. one’s digestive capacity for fruits

D. health values of fruits and vegetables

加热器水位过低或无水有什么危害？