只有在______精度很高时，重复定位才允许采用。
A．设计
B．定位基准和定位元件
C．加工
参考答案：B
I would really appreciate it if you could keep me _____ of how the negotiation is going on. [ ]
A. informed
B. informing
C. being informed
D. to be informed
何谓作物的三基点温度？试述作物的三基点温度有哪些规律？
