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问题 填空题

小李家离某书店6千米，他从家中出发步行到该书店，返回时由于步行速度比去时每小时慢了1千米，结果返回时多用了半小时．如果设小李去书店时的速度为每小时x千米，那么列出的方程是______．

答案

设小李去书店时的速度为每小时x千米，根据题意得：

6
x-1
-
6
x
=
1
2
，

故答案为：

6
x-1
-
6
x
=
1
2
．

单项选择题

Standard English is the variety of English which is usually used in print and which is normally taught in schools and to non-native speakers learning the language. It is also the variety which is normally (1) by educated people and used in news broadcasts and other (2) situations. The difference between standard and nonstandard, it should be noted, has (3) in principle to do with differences between formal and colloquial (4) ; standard English has colloquial as well as formal variants.

(5) , the standard variety of English is based on the London (6) of English that developed after the Norman Conquest resulted in the removal of the Court from Winchester to London. This dialect became the one (7) by the educated, and it was developed and promoted (8) a model, or norm, for wider and wider segments of society. It was also the (9) that was carried overseas, but not one unaffected by such export. Today, (10) English is arranged to the extent that tile grammar and vocabulary of English are (11) the same everywhere in the world where English is used; (12) among local standards is really quite minor, (13) the Singapore, South Africa, and Irish varieties are really very (14) different from one another so far as grammar and vocabulary are (15) .Indeed, Standard English is so powerful that it exerts a tremendous (16) on all local varieties, to the extent that many of long-established dialects of England have (17) much of their vigor and there is considerable pressure on them to be (18) . This latter situation is not unique (19) English: it is also true in other countries where processes of standardization are (20) .But it sometimes creates problems for speakers who try to strike some kind of compromise between local norms and national, even supranational ones.

2（）

A.same

B.similar

C.equal

D.identical
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问答题 简答题

炉子过冷向炉内添加热冰铜时应注意什么？
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