22．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
22．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
B
考查从句。第一个空考查定语从句，which 用于介词后指代前文的reports。第二个空是由that引导同位语从句。具体说明idea的详细内容。