现在完成时转换成一般过去时

 　　现在完成时可以转化成一般过去时，还可以转化成“It is/has been +时间段+since²从句(用一般过去时)”等句型。

　　e¹.g. Jim has been back for a month. 吉姆已经回来一个月了。 = Jim came³ back a month ago. 吉姆一个月前就回来了

　　= It is/has been a month since Jim came back. 自吉姆回来已经有一个月了。 = A month has passed since Jim came back. I have kept the book for two days. = I borrowed⁴ the book two days ago.

　　= It is / has been two days since I borrowed the book. = Two days has passed since I borrowed the book.

1 e   

n.英语字母表的第5个字母；C大调音阶中的第三音

参考例句：

• The "e" in " time" is a silent letter. time中的e不发音。 来自《简明英汉词典》
• You've made a mistake -- you've left out the letter e. 你出了一个错，把字母e 落了。 来自《现代汉英综合大词典》

2 since   

adv.后来；conj.既然，因为，自从；prep.自从

参考例句：

• He's been working in a bank since leaving school.自从毕业后，他就一直在一家银行工作。
• I have known him ever since I was a child.我自孩提时代起就已经认识他了。

3 came   

v.动词come的过去式

参考例句：

• I was surprised why he came here so early.他为什么那么早到这里，我很惊奇。
• The doctor came in time to save his life.医生及时来抢救他的生命。

4 borrowed   

adj.借来的

参考例句：

• I feel honor bound to repay the money I borrowed. 我觉得有责任归还我借的钱。
• I have left the watch as pledge for borrowed money. 我留下这块手表作为借款的抵押物。