问题补充：
The kind lady devoted all her life to those homeless children.
A. help
B. helping
C. be helping
D. being helped
答案：
A. help
(答案→)B. helping
C. be helping
D. being helped
解析：考查词组：devote all one’s life to doing一生致力于做…，这里的to是介词，后面接动名词做宾语，句意：这个好心的女士一生都致力于帮助那些无家可归的孩子。选B。
