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问题 选择题

中国新闻网2013年7月9日报道,通过变性手术,男性可以变成女性。先摘除男性生殖器官,再造女性外生殖器官。下列说法正确的是

A．手术后,该变性人能够产生月经

B．手术后,该变性人能够怀孕

C．手术后,该变性人失去男性第二性征

D．手术后,该变性人能够分泌雌性激素

答案

答案：C

题目分析：性激素能促进第二性征的出现，如男孩出现遗精，长出喉结，声音变粗等，女孩出现月经，骨盆变大等．由题意可知，易性术是只是把原有的外生殖器改变成异性的结构并切除性腺，只是改变了性器官和外部的某些特征，不能够分泌雌性激素，维持女性的第二性征，由此不会出现月经现象，也不会产生卵细胞，所以变性人不能够怀孕，但是由于变性人切除了性腺则失云浮男性第二性征，故选项C符合题意。

问答题

The produce departments of the future may look like nothing on earth, and with good reason. Chinese scientists have been growing tomatoes the size of softballs, cucumbers as long as baseball bats and other outsize fruits and vegetables, using seeds that have been shot into space. The seeds are then exposed to seven types of extraterrestrial conditions, from zero gravity and cosmic radiation to subatomic particles. (46) As these space veggies grow back on earth, they are selected for desirable traits--bulk, appearance or certain nutrients--then bred through successive generations to ensure that the mutations are consistent.
Chinese scientists don’t understand exactly how a trip into space alters the seeds’ DNA and yields such effects, but it’s not just size that changes. (47) Tong Yichao, whose firm, the Beijing Flying Eagle Green Foods Group, has been sending seeds and seedlings aboard Chinese spacecraft since 1999, says it has grown space tomatoes with 27 percent more of the antioxidant beta carotene than ordinary ones, and six-foot-tall cotton plants that produce longer, more flexible threads. Using conventional methods, "a scientist might create just three new plants in his lifetime," says Tong. "We’ve developed more than 50 since 1999."
(48) A dozen or so Chinese firms are paying up to $ 45 000 a gram to place various flora aboard satellites and manned spacecraft. The long-term goal: to feed more people and help endangered species escape extinction. To date, nearly 3 000 botanical species-including garden vegetables, medicinal herbs and flowers--have been sent into orbit and brought back to earth.
(49) The commercial promise of China’s space veggies has yet to, er, bear fruit. It’ s legal to sell the cosmic produce, and commercial farms have purchased some space plants. But most are being developed in labs or experimental greenhouses because no one wants to go to market before the safety and quality of the produce have been established. Even so, the idea of space flora is proving irresistible to a novelty-loving Chinese public. (50) When Tong displayed a handful of monster space eggplants--the largest of which weighed more than four pounds--at an expo, one disappeared before the show opened. Hot stuff, for sure.
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单项选择题

列车队较大故障修理简称（）。

A、较大故障修理

B、大件修

C、较大故障处理

D、列车队大件修
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