一、填空
1.He used to volunteer ___________(do) some work for the old.
2.I am writing in ___________(respond) to the questions you asked in the last letter.
3.Doctors performed an emergency ___________(operate) for appendicitis(阑尾炎) last night.
4.When it comes to campus ___________(secure) , we have to take it seriously.
5.I received an encouraging r to my advertisement.
6.People used to think the earth was f .
7.A t is a person whose job is to count votes, especially in a parliament.
