不定项选择

涡旋电场是由变化的磁场激发的。

A．正确
B．错误

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单项选择题

What happened to his family after the atomic explosion?
A、His youngest sister survived.
B、His mother was with his younger brother and younger sister.
C、His mother and elder sister were missing
D、He lost 5 family members.

单项选择题

40年代持续最久、影响最大的杂文刊物是（）
A、《野草》
B、《鲁迅风》
C、《杂文丛刊》
D、《野火》