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【单选题】
用硅藻土杀虫剂制作防虫线时,硅藻土要过直径为( )的圆孔筛。
A.
1.0mm
B.
1.5mm
C.
2.0mm
D.
2.5mm
参考答案：
参考解析：
刷刷题刷刷变学霸
举一反三
【单选题】很多国家已停止使用含铊的杀虫剂。元素周期表中铊的数据见右图，下列说法正确的是
A.
TI元素是一种主族元素
B.
TI元素的相对原子质量是204
C.
铊元素的质量数是204.4
D.
TI原子最外层有3个能量相同的电子
【单选题】Many Americans harbor a grossly distorted and exaggerated view of most of the risks surrounding food．Fergus Clydesdale, head of the department of food science and nutrition at the University of Massac...
A.
They overlook the risks of the food they eat.
B.
They overestimate the hazards of their food.
C.
They are overoptimistic about the safety of their food.
D.
They overstate the government's interference with the food industry.