Researchers have found clear and convincing evidence ________ happiness isthe key to better health a

题目简介

Researchers have found clear and convincing evidence ________ happiness is
the key to better health and longer lives.

A．where

B．whether

C．how

D．that

题型：单选题难度：中档来源：不详

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。