Laughter, along with an active sense of humor, protect you against a heart attack, according to a recent study.
A. have helped
B. helped
C. help
D. helps
网友回答
A. have helped
B. helped
C. help
(答案→)D. helps
解析：本句的主语是laughter，和后面的an active sense of humor没关系，故谓语动词使用单数形式。句义：根据最近的一项调查，笑声和幽默感可以帮助保护我们不受心脏病的攻击。本句中没有出现过去时的时间状语，而且是对经常性的事情的说明，故D正确。