I sped along that highway at 160 mph.

我以160MPH沿着高速公路超速行驶

—Oh, my God. You can never do that again. You ______ yourself. 

哦，天啦，你千万不要再做了，你可能会没命的( could do sth表示理论上是有可能发生的，但是实际未必会发生）

A. could kill       B. could have killed

选A，表示推测，可能意思

could have done sth 有以下2层含义

1. 可能已经做了某事(表示把握性不大推测）

He could have gone home.

他可能已经回去了

2.本来可以/本来能做某事，却没有做某事（与事实相反的假设）

 He thought she could have done better, by far. 
他认为她本可以演得更好, 而且是好得多.

 I could have traveled, I could have done all kinds of things. 
我本来可以去旅行, 我本来可以做所有事情.

以上题目来自下面权威英语试题

1. I would appreciate______ greatly if you could give me a three-day leave.

A. you    B. it        C. that       D. myself

2.--------- Would you mind my using your computer for a while?

--------- ____________.

A. Yes, go ahead         B. Of course, help yourself

C. Absolutely not         D. Sure, but it’s broken down

3. It may rain, but we should go ________.

A. anyway     B. though       C. certainly      D. however

4. After work they______ all their tools and kept them in the cupboard.

A. put on     B. put away        C. put out        D. put up

5. There is more and more doubt ______ the UN resolution aimed at stopping humanitarian crisis in Lybia has been abused.

A. if     B. that        C. /       D. whether

6. Environment makes _____ we are. If we damage the environment, we’ll endanger ourselves.

A. how    B. who        C. what        D. before

7. Such animals as South China tigers are believed _____, for we’ve had no track of them for ages.

A. becoming  extinct         B. to become

C. to have been extinct       D. having been extinct

8.----- I sped along that highway at 160 mph.

------- Oh, my God. You can never do that again. You ______yourself.

A. should kill    B. could kill

C. should have killed      D. could have killed

9. Weeks after the big earthquake in Japan, hundreds of people remained struggling in their ruined homeland, _____ to be rescued.

A. waiting      B. to wait         C. waited       D. being waited

10. Frequently there is so much traffic in the street in the rush hour that you can hardly get _____ even on foot.

A. over      B. through        C. across      D. beyond

11. Lucy ______ volleyball  regularly for many years when she was young.

A. played   B. was playing        C. has played       D. had played

12. You should ______ making promises you can’t keep.

A. prevent     B. allow        C. protect       D. avoid

13. The novel The Adventures of Huckleberry Finn was written by_____.

A. Henry James                B. Mark Twain

C. Harriet  Beecher Stowe       D. O Henry

14.Which of the following English sounds is NOT bilabial?

A. [b]       B. [m]        C. [p]        D. [f]

15.The English word “untouchable” is composed of _______morphemes.

A. two       B. three        C. four        D. five

sped along发生在过去，所以说话人站在现在的立场说“你那时可能杀了自己“

你把它看作could +killed,但是could后面要加原型所以要变成could have done，又因为实际上没有发生，与事实不等，所以是虚拟

我也是经过语法探等老师的帮助才理解了