英语问题When the teacher ____the classroom,all the students stoo

英语问题
When the teacher ____the classroom,all the students stood up.
A.came B.appeared C.arrived D.entered
--Why are you so late for work today?
--______to the office was very slow this morning because of the traffic accident.
A.Driving B.That driving.
应该选什么?为什么吖?详细点好吗.谢谢.