—Are you a volunteer now? —No, but I ___
题型：选择题
问题：
—Are you a volunteer now?
—No, but I _____. I worked for the City Sports Meeting last year.
A．used to
B．used to be
C．used to do
D．was used to
—Are you a volunteer now?
—No, but I _____. I worked for the City Sports Meeting last year.
A．used to
B．used to be
C．used to do
D．was used to