疏松砂岩层的砂样在装袋时,要捣碎,散砂可以丢掉。
参考答案:错
Mum has always made me ________ my skin problem and encouraged me to use the cream.
A.aware of
B.compared to
C.familiar with
D.accustomed to
通过头部运动用以辨别声源方向的是()。
A.前庭器官
B.柯蒂器
C.两者均有关
D.两者均无关