We’re conducting a nationwide survey of people’s reading habits. Would you have five minutes ________ a few questions?         

A．answering

B．to answer

C．to have answered

D．having answered

牙体修复过程中，不利于牙髓保护的是（）

A.牙体制备过程中喷水降温

B.牙体制备完成后戴用暂时冠

C.选用对牙髓刺激小的粘结剂

D.牙体制备过程中加大压力，使切割尽快完成

E.修复体边缘密合