问题
选择题
. He made up his mind to devote his life____________the river____________polluted.
A．to prevent, to be
B．to prevent, from being
C．to preventing, to be
D．to preventing, from being
答案
答案：D
考查devote和prevent的用法。Devoteto致力于……，把……专注于，To是介词，后面接名词或者动名词。Prevent……from，From为介词，后面接名词或者动名词。阻止，预防某人干某事。句意：他决定把他的医生致力于防止河流免于污染的事业中。故选D。