Question

【题目】It is through years of research ________ scientists have discovered the relationship between social media addiction and depression.

A. sinceB. beforeC. thatD. when

Answer 1

【答案】C

【解析】

考查强调句型。句意：通过多年的研究，科学家们发现了社交媒体成瘾和抑郁症之间的关系。此处是强调句型，故答案为C。