平行空孔直线掏槽有()三种类型。
参考答案:龟裂、筒形、螺旋式
I heard the alarm ringing all the morning. ____ something very urgent happened.
A.Really
B.Obviously
C.Especially
D.Terribly
可用于比较坐高与头围的变异度的是()
A.Qu-QL
B.S
C.CV
D.S2
E.R