The determined mother has devoted all she has to her son out of trouble.
A. helping
B. help
C. have helped
D. having helped
网友回答
(答案→)A. helping
B. help
C. have helped
D. having helped
解析：devote后面加to sth或者to doing sth。 to在这里属于介词，后面应该接名词或v-ing形式，所以，应该是devote oneself to sth/ doing sth。D选项表示已经完成了动作，不符题意，故选A.