The determined mother has devoted all she has to ________ her son out of trouble.A.helpingB.helpC.have helpedD.having helped
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A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.