双基限时练(十九) module 5 section ⅲ 基 础 夯 实 ⅰ.短语填空 break down； as far as； rely on； up and down； up to； put out； on the contrary； knock out； by mistake； make sure 1．mr. white may be at home, but you'd better call and ____________. 答案 make sure 2．these psychological barriers are difficult to ____________. 答案 break down
