我们把依次连接任意一个四边形各边中点所得的四边形叫做中点四边形,若一个四边形ABCD的中点四边形是一个矩形,则四边形ABCD可以是( )。(写出一个你认为正确的结论即可)
正方形
__________ , some students tend to develop a range of unhealthy habits .
A.Parents don’t watch over them
B.Not having watched over
C.With no parents to watch over them
D.Parents watched over
后腭杆的宽度约为()
A.2mm
B.3mm
C.5mm
D.7mm
E.10mm