1rad约等于______。
A.180°
B.57.296°
C.0.017°
参考答案:B
Throughout______ history, ______ English language is made up of the rules each group of people brought to Britain with them.
A.the, the
B./,the
C.the,/
D./,/
胎儿生长发育过程中的周围环境是( )
A.血液
B.羊水
C.胎盘
D.羊膜