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问题 选择题

关于蝗虫不完全变态的发育过程，表述正确的是

A．卵→幼虫→蛹→成虫

B．卵→若虫→成虫

C．卵→成虫→蛹

D．若虫→成虫→蛹→卵

答案

答案：B

题目分析：不完全变态发育：幼体与成体的形态结构和生活习性非常相似，但各方面未发育成熟，发育经历卵、若虫、成虫三个时期，例如：蝗虫、蟋蟀、蝼蛄、螳螂、蜻蜓的发育经历卵、若虫、成虫三个时期，属于不完全变态发育，故选B。

单项选择题

In country after country, talk of nonsmoker’s right is in the air. While a majority of countries have taken little (51) no action yet, some 30 nations have introduced legislated steps to control smoking. Many laws have been introduced in other countries to (52) clear the air for nonsmokers, or to cut cigarette consumption.

Smoking is harmful (53) the health of people. World governments should conduct serious campaigns against it. (54) on cigarette advertisements, plus health warnings on packages and ban on public smoking in certain places, (55) as theaters, cinemas and restaurants, are the most popular tools used by nations in (56) of nonsmokers or in controlling smoking. But world attention is also focusing on another step (57) will make the smoker increasingly self-conscious and uncomfortable about his habit. Great efforts should be made to (58) young people especially of the dreadful consequences of taking up the habit. And cigarette price should be raised.

In the long run, (59) is no doubt that everybody would be much better-off if smoking were banned altogether but many people are not (60) for such drastic action.

55().

A.such 

B.even 

C.so 

D.not
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问答题 简答题

果树年生长周期
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