Mary is always ready to do some work at the local geraium（敬老院）in her spare time.
A. responsible
Bexhausting
C. voluntary
D. professional
网友回答
A. responsible
B. exhausting
(答案→)C. voluntary
D. professional
解析：句意为：玛丽总是乐意在业余时间到当地的敬老院做些志愿工作。voluntary“志愿的；无偿的；自愿的”；符合句意。responsible“有责任的；负责的”； exhausting“令人筋疲力尽的；使人疲惫不堪的”； professional“专业的”。