In my opinion, all Mr Li ______ good to his students in his class at present. He is very strict with them in their studies.

A．does does does

B．does does do

C．does do did

D．did do does

在工程网络计划执行过程中，如果某工作进度拖后，则受影响的工作一定是该工作的（）。

A.平行工作

B.后续工作

C.先行工作

D.紧前工作