问题
选择题
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
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.