下列生物不属于变态发育的是（ ）
A．鸡发育成大公鸡
B．蝇的幼虫发育成蝇
C．雏蝌蚪发育成蛙
D．孑孓（蚊子幼虫）发育成蚊子
变态发育指动物在胚后发育过程中，形态结构和生活习性上所出现的一系列显著变化．幼体与成体差别很大，而且改变的形态又是集中在短时间内完成，这种胚后发育叫变态发育，特指昆虫和两栖动物．
A、变态发育一般指昆虫和两栖类，幼体与成体差别很大，鸡是鸟类，幼体与成体差别不大，不属于变态发育，故该选项符合题意；
B、蝇的幼虫发育成蝇，蝇的幼虫叫蝇蛆，没有翅，爬行，蝇有翅以飞行为主，幼体与成体差别很大，属于变态发育，并且是完全变态发育．故该选项不符合题意；
C、蝌蚪发育成蛙，蝌蚪生活在水中，用鳃呼吸；蛙水陆两栖，用肺呼吸，幼体与成体差别很大，属于变态发育，故该选项不符合题意；
D、孑孓生活在水里，没有翅，蚊子有翅，飞行为主，幼体与成体差别很大，属于变态发育，并且是完全变态发育，故该选项不符合题意．
故选：A．
| Cloze test. | ||||
| One topic is rarely mentioned in all the talk of improving standards in our schools: the almost complete failure of the foreign-language teaching. As a French graduate who has taught for more than twenty-five years, I believe I have some idea of why the failure is so total. 1 the faults already found out in the education system as a whole-such as child-centred learning. The "discovery" method, and the low expectations by teachers of pupils-there have been several serious 2 which have a direct effect on language teaching. The first is the removal from the curriculum (课程) of the thorough teaching of English 3 . Pupils now do not know a verb from a noun, the subject of a sentence from its object, or the difference between the past, present, or future. Another important error is mixed-ability teaching, or teaching in ability groups so 4 that the most able pupils are 5 and are bored while the least able are lost and 6 bored. Strangely enough, few head teachers seem to be in favour of mixed-ability school football teams. Progress depends on memory, and pupils start to forget immediately they stop having 7 lessons. This is why many people who attended French lessons at school, even those who got good grades, have forgotten it a few years later. 8 they never need it, they do not practise it. Most American schools have accepted what is inevitable and 9 modern languages, even Spanish, from the curriculum. Perhaps it is time for Britain to do the same, and stop 10 resources on a subject which few pupils want or need. | ||||
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