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问题 选择题

如图所示是射箭的情景，将箭射向远处直至落地的过程中，下列说法错误的是：

[ ]

A．将弓拉开静止时，箭所受的合力为0

B．将箭射出时，力对箭做了功

C．箭在空中飞行的路线是直线

D．将箭射出时，弓的机械能转化为箭的动能

答案

答案：C

问答题 简答题

试说明一段高负荷生物滤池几种回流形式。
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单项选择题

In every cultivated language there are two great classes of words which, taken together, comprises the whole vocabulary. First, there are those words (1) which we become acquainted in daily conversation, which we (2) , that is to say, from the (3) of our own family and from our familiar associates, and (4) we should know and use (5) we could not read or write. They (6) the common things of life, and are the stock in trade of all who (7) the language. Such words may be called "popular", since they belong to the people (8) and are not the exclusive (9) of a limited class.

On the other hand, our language (10) a multitude of words which are comparatively (11) used in ordinary conversation. Their meanings are known to every educated person, but there is little (12) to use them at home or in the market-place. Our (13) acquaintance with them comes not from our mother’s (14) or from the talk of our school-mates, (15) from books that we read, lectures that we (16) , or the more (17) conversation of highly educated speakers who are discussing some particular (18) in a style appropriately elevated above the habitual (19) of everyday life. Such words are called "learned", and the (20) between them and the "popular" words is of great importance to a right understanding of linguistic process.

12（）

A.prospect

B.way

C.reason

D.necessity
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