第17题: [单项选择]The National Institute of Mental Health is conducting a far-reaching research to determine the psychological effects of using drug. A. extensive B. refined C. prevalent D. tentative 参考答案:A 答案解析:画线词far-reaching:意义深远的,选项A.extensive可以替代它,但说不上是同义词。辨义:A.extensive范围广泛的,意义深远的;B.refined精练的,经过提炼的; C.pr