一般能自根上长出不定芽的花卉可采用（）插法。A.硬枝 B.嫩枝 C.根 D.叶

There’s no point in trying to ________with her because she will never change her mind.

A．agree

B．compete

C．compare

D．reason

I _____ my teacher since last year. I miss him very much. [ ]

A. didn't

B. saw

C. haven't seen

人力资源配置的基本原理是（）。

A.能级层序原理

B.同素异构原理

C.适应原理

D.量能原理

沉淀反应形成的反应现象（）（）

A.肉眼可见

B.肉眼不可见

C.必须用精密仪器测定

D.必须染色才可见

E.经电泳后可见

一电缆标有3×4+1×2.5，它的含义是什么？