关于精馏段的表述，错误的是（）。A、液相回流是精馏段操作的必

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问题单项选择题

关于精馏段的表述，错误的是（）。

A、液相回流是精馏段操作的必要条件

B、精馏段顶部的轻组分浓度高

C、液相回流中轻组分浓度自上而下不断减少，而温度不断上升

D、精馏段的作用是将进料的液相组分提浓

答案

参考答案：D

填空题

根据下图所示情景，补上短文中所缺单词或短语

The (1)__________ night Jim (2)__________ very late(watched TV far into the night).When he

(3)__________ up in the morning, Jim found that it was already (4)__________ o'clock. He thought

he would be (5)__________ for school and felt very (6)__________. He (7)__________ up quickly,

took his schoolbag and (8)__________ to school without breakfast. When he (9)__________ school,

he found it was quiet and nobody else had come. He realized it was (10)__________ and he had made

a mistake.

单项选择题

药材斑蝥的来源是（）

A.斑蝥科动物斑蝥及小斑蝥的干燥虫体

B.芫菁科动物斑蝥及小斑蝥的干燥虫体

C.斑蝥科动物南方大斑蜜及黄黑小斑蝥的干燥体

D.芫菁科动物南方大斑蝥及黄黑小斑蝥的干燥体

E.斑蝥科动物斑蝥及小斑蝥的雌虫干燥体