由三个蓄电池串联的蓄电池组电压为_______伏,照明电路电压为_______伏,人的安全电压为_______伏。
6;220;不高于36
Don't forget ________ the medicine before you go to bed.[ ]
A. take
B. taking
C. to take
D. took
已知线段AB=6cm,在线段AB所在的直线上截取BC=4cm,则AC=______.