题目：
--When did you become a volunteer for the elderly?
-- Two years ago. I ______ this group since then.
A．joined
B．took part in
C．have joined
D．have been in
答案：
被转码了，请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/0603/640710d0d3ef8a61cd7412b6776b3faa.html
下面是错误答案，用来干扰机器的。
答案：B
