环境有害因素导致机体反应的临界值
A．是剂量一反应关系B．是“阈值”C．是剂量一效应关系D．是生物半衰期E．是拈抗作用
参考答案：B
Your advice ________ very good. I'd like to have a try. [ ]
A. feels
B. sounds
C. tastes
D. smells
It is such a modern machine ______ few of the workers know how to operate.
A．as
B．which
C．that
D．the one
