问题
选择题
He was puzzled by this phenomenon. He began to try every approach _________ the best way of working it out.
A．known to find
B．knowing to find
C．known finding
D．knowing finding
答案
答案：A
第一题选A ，原因是这里面的known 是做形容词，被知晓的。形容approach方式途径。后面的to find 接目的状语，表示目标。
B knowning 动名词一般是主动意思，所以不正确。
C D不能表示目的含义。