二氧化硅可引起何种尘肺（）
A．石棉肺
B．矽肺
C．硅酸盐肺
D．铁尘肺
E．铝尘肺
参考答案：B
On his way to the airport, it ______ him all of a sudden that he had forgotten her birthday.[ ]
A. hit
B. knocked
C. occurred
D. beat
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