问题
选择题
Some ______are ______their time to help the old people.
A．volunteer; volunteer
B．volunteers; volunteering
C．volunteering; volunteers
D．volunteers; volunteers
答案
答案：B
题目分析：句意：一些志愿者在自愿花时间帮助老人。volunteer志愿者，名词，volunteer to do sth.自愿去做某事，动词，这是一个现在进行时的句子，故选B。