just as people take time to learn how to drive safely, so do machines. And machines are not quick learners. The RAND Corporation calculates that to develop a system 20% safer than a human driver, 100 self- driving ...
A: so B:andC: when D: before 要记考点:1、when考点只有一个“主将从现”,2、before的考点只有一个:it is long times before+从句; so考点是一些固定搭配。 1、宾语从句的四种形式: ①主语+谓语(及物动词do)+从句 He knowstha...