-My parents our home for a few hours when I arrived. I didn't meet them.-You could call them if you wanted to know where they were.
A:have been away from
B:had been away from
C:had left
D:had gone
班级开展“青春畅想”综合性学习活动,请你积极参与下列活动。
用塑料梳子在干燥的头发上梳几下,梳子上会带电,经检验梳子带的是负电荷.下列说法中正确的是( )