砖基础大放脚摆放,宜先从摆放()开始。A、轴线B、两端C、转角

题型:单项选择题

问题:

砖基础大放脚摆放,宜先从摆放()开始。

A、轴线

B、两端

C、转角

考点:砌筑工砌筑工题库
题型:单项选择题

算法复杂度主要包括时间复杂度和______复杂度。

题型:单项选择题

有关脊髓空洞症的临床表现特点,下列错误的是()。

A.节段性分离性障碍

B.常伴有Chiari畸形

C.一侧或两侧鱼际肌、骨间肌萎缩

D.可出现Charcot关节

E.常呈急性发病

题型:单项选择题

转变为的方法为[ ]

A.与足量的NaOH溶液共热后,再通入CO2

B.溶液加热,通入足量的HCl

C.与稀H2SO4共热后,加入足量的Na2CO3

D.与稀H2SO4共热后,加入足量的NaOH

题型:单项选择题

要显示当前过程中的所有变量及对象的取值,可以利用( )窗口。

A.数据

B.调用堆栈

C.立即

D.本地

题型:单项选择题

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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