爸爸每工作4天休息一天,妈妈每工作5天休息一天。他们在9月1日同时休息,那么他们下一次同时休息的日期是( )。
10月1日
—He didn't go to the concert yesterday, did he?
—_____. He was busy studying for the tests all day.[ ]
A. No, he didn't
B. Yes, he did
C. No, he did
D. Yes, he didn't
控制道岔侧向速度的部位主要是()。