_________to nuclear radiation, even for a short time, may produce variants of ge

题干

_________to nuclear radiation, even for a short time, may produce variants of genes in human bodies.

A．Being close	B．Having been closed
C．Closed	D．After being closed

上一题下一题 0.65难度单项选择更新时间:2017-07-18 06:36:44

小学学科试题库

初中学科试题库

高中学科试题库