Researchers have found clear and convincing evidence happiness is the key to bet

Researchers havefound clear and convincing evidence ________ happiness is

the key to betterhealth and longer lives.

  A. where          B.whether          C. how       D.that

试题答案

【答案】

D

【解析】考察同位语从句.同位语从句that happiness is the key to better health and longer lives解释名词evidence的内容。