鲫鱼在水中口和鳃盖后缘不停的交替开闭,其主要作用是 [ ]
A.调节比重
B.平衡身体
C.进行呼吸
D.防御敌害
答案:C
— Who is the girl standing over there?
— Well, if you _____ know, her name is Mabel. [ ]
A. may
B. can
C. must
D. shall
家用电器着火时,正确的扑救方法为()
A、立即拉闸断电或拔下插头
B、直接用湿毛毯或棉被捂盖
C、直接用水扑救
D、以上都是