⑴The man is falling down the stairs.____
⑵The birds are flying away.____
⑶She is getting off the bus____
⑷My mum is on the phone.____
⑸They are having a birthday party.____
A. B. C. D. E.
从左到右、从下到上依次填写)
3cos10°-1sin170°= ( )
是锐角三角形的有:____;是钝角三角形的有:____。是直角三角形的有:____;是等边三角形的有:____。
如图所示,在探究影响导体电阻大小因素的实验中,导线a、b、c粗细相同,b、d粗细不同; a、b、d长度不同