9. When did the accident happen?
交通事故是什么时候发生的?
还能这样说：
What time did the accident happen?
When did the accident take place?
谚语：
Accidents will happen in the best-regulated families.
家规再严，丑事难免。
10. He was to blame or the traffic accident.
他应该对这一交通事故负责任。
还能这样说：
He was responsible for the traffic accident.
He should take the responsibility for the accident.
应用解析：
blame sb. for the failure 因失败而责怪某人;
blame on 把责任推给……
11. I witness a traffic accident on my way home.
我在回家的路上亲眼目睹了一场交通事故。
还能这样说：
I am a witness to the traffic accident on my way home.
I witness the traffic accident when I go home.
应用解析：
bear false witness against sb. 做对某人不利的伪证;
in witness of 作为……的证明，为……做证
12. I was petrified when two cars collided.
两车相撞的情景把我吓呆了。
还能这样说：
I was struck by the two collided cars.
I was terrified by the sight which two cars clashed.
还能这样说：
The accident was caused by the dense fog.
The fog led to the accident.
应用解析：
responsible for 对某人负责
应用解析：
have an accident 遭受意外;
meet with an accident 遭不测，失事;
without accident 平安无恙地;
by accident 偶然