设在x=0处连续,且,则a=()
A.2
B.-2
C.
D.
参考答案:D
— _____
— He is a bank clerk. [ ]
A. Why does he like koalas?
B. What does your father look like?
C. Where is your father from?
D. What does your father do?
固液界面的微观结构描述不正确的是()
A、光滑界面,从原子尺度看,界面是光滑平整的
B、在光学显微镜下,光滑界面是由若干 * * 面组成的,又称为 * * 面界面
C、粗糙界面又称为非 * * 面界面
D、粗糙界面,在光学显微镜下,界面是高低不平的