1021.The old lady's hand shook frequently. She explained to her doctor _____ this shaking had begun half a year before, and ____，only because of this, she had been forced to give up her job.
A.when；how
B.how；when
C.how；how
D.why；why
1022.The shopkeeper did not want to sell for ___ he thought was not enough.
A.where
B.how
C.what
D.which
1021.答案是C;此题中how 引导两个宾语从句。
1022.答案是C;what引导从句作介词for的宾语，且what在从句中作主语。
