Experiments of this kind ________ in both the U.S. and Europe long before the Se

题干

Experiments of this kind ________ in both the U.S. and Europe long before the Second World War.

A．conducted	B．was conducted
C．had been conducted	D．had conducted

上一题下一题 0.64难度单项选择更新时间:2014-12-30 06:02:04

小学学科试题库

初中学科试题库

高中学科试题库