结晶方向不同的、直接接触的同成分晶粒间的交界处称为相界.
参考答案：错
I have _____ all my papers but I still can't find my notes. [ ]
A. looked through
B. looked for
C. looked after
D. looked out
开尔文所说的物理学中两朵乌云，一是黑体辐射，另一个是什么？（）
