The determined mother has devoted all she has to her son out of trouble.A. helpingB. help

问题补充：

The determined mother has devoted all she has to her son out of trouble.

A. helping

B. help

C. have helped

D. having helped

答案：

(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.