1. I´ll enclose your letter with mine.
    我把你的信装在我的信里.

2. I think that book is mine.
    那本书是我的.

3. If explosives are used, vibrations will cause the roof of the mine to collapse.
    若是用爆破方法，震动会使矿井的顶部倒塌。

4. If explosives are used, vibrations will cause the roof of the mine to collapse.
    如果用炸药爆破，震动会引起矿顶塌落。

5. It happened to a friend of mine a year ago.
    这是一年前发生在我的一个朋友身上的故事。

6. It was difficult to coordinate our steps — his halting, mine impatient — and because of that, we didn't say much as we went along.
    我们的步伐难以协调一致--他常常停下脚步，而我的步子却显得不耐烦--正因如此, 我们一路很少说话。

7. It is thrilling to think, to know, that for any act of mine, I shall get twice as much praise or twice as much blame.
    不管我做什么，都可能得到双倍的嘉奖，或是双份的责难。