So difficult did he find to pass the driving test that he decided to give up.
A. how
B. that
C. which
D. it
网友回答
A. how
B. that
C. which
(答案→)D. it
解析：考查it的用法：这句话是倒装句，改成正常语序是He found it so difficult to pass the driving test that he decided to give up.句型是find it+adj+to do作形式宾主语替代不定式，句意：他发现通过驾驶测试是如此难，以至于他决定放弃。选D。