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问题 单项选择题

下列在易燃易爆环境下安装仪表的要求，错误的是（）。

A.本质安全型线路敷设完毕，要用50HZ，500V交流电压进行1分钟试验，没有击穿，表明其绝缘性能已符合要求

B.本质安全线路和非本质安全线路可以合穿在一根保护套管内

C.全部保护套管必须密封

D.保护套管应用管卡牢固固定，不能用焊接方法固定

答案

参考答案：B

单项选择题

Many word processing programs include spell checker. It checks the spelling of every word in a (120) by looking up each word in its dictionary. If the word does not appear in the dictionary the user is (121) to possible misspelling and possible corrections are often (122) . Spell checker does not recognize unusual people names or specialized terms, but it will often allow you to create your own personal dictionary of specialized words you often use. Spell checker is a valuable aid to proofreading, but it can not catch the (123) of one correctly spelled word for another (such as form for from). Thus it does not (124) a document is free of spelling errors.

（120）处是（）

A.document

B.equipment

C.program

D.statement
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单项选择题

《价格法》规定了（）定价目录。

A.一级

B.两级

C.三级

D.四级
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