光波在非均质体的传播特点?
参考答案:
光波射入非均质体中,除特殊方向之外,都要发生双折射,分解成振动方向相互垂直,传播速度不同,相应折射率值不等的两种偏光。
Jack has gone to Australia, but I'm wondering why he ______ in such a hurry.[ ]
A. left
B. has left
C. leaves
D. was leaving
什么是中毒?