He is very popular among his students as he always tries to make them ____

in his lectures.

A．interested

B．interesting

C．interest

D．to interest

用端铣刀铣阶台面，比较适合于加工有较宽水平面的阶台。由于铣刀直径大，长度小，可取较大的切削用量，故生产效率高。