重悬浮液的稳定性是指悬浮液各处密度维持()
A.不变
B.均匀变化
C.界限明显
参考答案:A
We often practice________ English among ourselves. [ ]
A. speak
B. to speak
C. speaking
D. spoken
胡服的特点是宽衣博带长袖。