Lawrence Craven,a doctor from the USA,is the author of several published reports,one of introduced the idea in 1953 aspirin could reduce the risk of heart attacks.
A. them; when
B. which; that
C. what;that
D. which; when
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A. them; when
(答案→)B. which; that
C. what;that
D. which; when
解析：本题同时考查非限制性定语从句和名词性从句中的同位语从句，故第一空用which，第二空用that。