单项选择题

大气层又叫大气圈，地球就被这一层很厚的大气层包围着。下列关于大气层的说法中，正确的一项是( )。

A．大气层的厚度大约为700千米
B．云、雾、雨等现象都发生在暖层内
C．大气层的气温随高度增加而降低
D．大气层的空气密度随高度的增加而减小
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单项选择题
We have received orders ______ USD 1,000,000 since the new product was introduced to the market.
A．amount for
B．amount to
C．account for
D．amounting to
单项选择题
According to the Customs Law, while the examination is being carried out, （） should be present and responsible for moving the goods, opening and restoring the packing.

A. customs officer
B. harbor officer
C. the consignee of the import goods or the consignor of the export goods
D. the owner of the ship
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