牙骨质龋属于
A.慢性龋
B.浅龋
C.中龋
D.深龋
E.继发龋
参考答案:B
菱形的周长为8.4cm ,相邻两角之比为5:1 ,那么菱形一组对边之间的距离为 [ ]
A.1. 05cm
B.0.525cm
C.4. 2cm
D.2.1cm
Let's _________ outside now.[ ]
A. going
B. to go
C. go
D. goes