1. Most doctors of the Colonial period believed _______ was caused by an imbalance of humors in the body.
A. in disease
B. that disease
C. of disease
D. about disease
2. In 1976 Sarah Caldwell became _________ at the Metropolitan Opera House in New York City.
A. she was the first woman to conduct
B. the first woman conductor
C. the woman was first conducting
D. the woman conducts first
3. On January 7， 1955， Marian Anderson became _________ to sing a major role at New York City's Metropolitan Opera House.
A. the first African American
B. the first African American was
C. she was the first African American
D. when the first African American
4. Perhaps the most significant postwar trend was the decentralization of cities throughout the United States， _________ when massive highway-building programs permitted greater suburban growth.
A. and accelerated a phenomenon
B. a phenomenon that accelerated
C. accelerating a phenomenon which，
D. the acceleration of which phenomenon
5. Ronald Reagan had served two terms as governor of California before _________ President.
A. he became
B. when becoming
D. did he become