无论是测直流电或交流电,验电器的氖灯炮发光情况是一样的。()
参考答案:错
It was in 1969 ______ two Americans went to the moon by spaceship.
A.when
B.that
C.at that time
D.just then
在Visual FoxPro的参照完整性规则不包括
A.更新规则
B.删除规则
C.查询规则
D.插入规则