三、例題
1. Only recently ______ to realize the dangers caffeine ( 咖啡因) might bring to our health.

A. that scientists began        B. have scientists begun
C. scientists have begun       D. that did scientists begin
2. Not until the year of 1954 ______ made the capital of this country.
A. the city was              B. was the city
C. when the city was         D. was when the city
3. ______ the doctor right away, he might be alive today.
A. Should he have gone to          B. If he went to
C. Were he to go                  D. Had he gone to
4. “Does your father call you very often?” “Yes, my father calls about once a week and ______.”
A. so my brother does        B. my brother does so
C. so does my brother        D. does so my brother
5. Hardly anything ______ more th