根据英语翻译下面短语的意思并完成句子。

1. by chance _____        

2. by accident _____

3. by mistake _____                  

4.  by luck_____

5. by design _____

6. by good fortune_____

7. by necessity_____

8. I met an old friend of mine _____  in the street.

  我在街上偶然碰到了老朋友.

9. — How did you find your lost bike?

        你如何找到的你丢失的自行车?

    — _____.

         凑巧找到的.

10. I had no trouble passing on the driving test in the end ___.

      由于运气好最后我通过了驾照考试.

11. He has finished his task ahead of time______.

      由于进行了周密的筹划,他提前完成了任务.

12. The war will break out between the United Sates and Iran_____ in time.

      伊美之间迟早会不可避免地爆发战争.

试论述企业的短期和长期目标。