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问题 选择题

X是ⅡA族的金属元素，Y是ⅥA族的非金属元素。那么，由X和Y形成的离子化合物的化学式是[ ]

A．XY

B．X2Y

C．XY2

D．X2Y3

答案

答案：A

单项选择题

Amateur cooks have joined the craze with the help of more than 20 cookbooks which devote exclusively with hot and spicy Mexican, Thai and Cajun foods.

A．that devote exclusively to

B．devoting exclusively of

C．that devotes exclusively with

D．that devoting exclusively to
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单项选择题

双夹送辊的辊面长为（）。

A.1300mm

B.1080mm

C.1200mm

D.1000mm
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