单选题He promised to do wh

问题补充：

单选题Hepromisedtodowhathe______sureof_______.A.could make; my happyB.could to make; me happyC.could make; my happinessD.could to make; my happiness

答案：

D解析本题句意“他许诺做他能做的保证使我幸福”。what he could (do)to make sure of my happiness，其中to make sure of my happiness做状语。