The temperature of our earth will become higher and higher _____ we take actions right now. [ ]

A. unless

B. if

C. as soon as

D. as

下面引起在半径补偿时产生过切现象的原因中（）是错误的。

A.加工半径小于刀具半径

B.被铣削槽底宽小于刀具直径

C.加工比刀具半径小的台阶

D.刀具伸出过长