问题
选择题
In __________ review off 44 studies, American researchers found that men and women who ate six key foods daily cut the risk of __________ heart disease by 76%.
A．a; the
B．the; a
C．a; 不填
D．不填; a
答案
答案：C
第一空填不定冠词，表示“一次”；第二空不填冠词(或填零冠词)，因为此处是表泛指。