一、從結(jié)構(gòu)上區(qū)別
現(xiàn)在完成時(shí):主語(yǔ) + have / has + 過(guò)去分詞 (肯定式)
主語(yǔ) + have / has + not + 過(guò)去分詞 (否定式)
Have / Has + 主語(yǔ) + 過(guò)去分詞 (疑問(wèn)式)
過(guò)去完成時(shí):主語(yǔ) + had + 過(guò)去分詞 (肯定式)
主語(yǔ) +had + not + 過(guò)去分詞 (否定式)
Had + 主語(yǔ) + 過(guò)去分詞 (疑問(wèn)式)
(二)從時(shí)間狀語(yǔ)區(qū)別
現(xiàn)在完成時(shí): 常用的時(shí)間狀語(yǔ)包括 “now, today, tonight, this week, this year, already, yet, just, recently…etc”。
過(guò)去完成時(shí): 常用的時(shí)間狀語(yǔ)包括 “by, at, before等構(gòu)成的短語(yǔ)”。
注意:當(dāng)表示一段時(shí)間,現(xiàn)在完成時(shí)和過(guò)去完成時(shí)都可以用for 或since引導(dǎo)的狀語(yǔ)。

例如:Have you had your lunch yet?

你吃午飯了嗎?

Yes, I have . I’ve just had it.

是的,我剛吃完。

I have had a clock now.

我現(xiàn)在有一個(gè)鬧鐘了。

Have you already posted the photos?

你把照片寄走了嗎?

The meeting had begun when we got there.

我們到那兒時(shí),會(huì)議已經(jīng)開(kāi)始了。

We had learned about 5000English words by the end of last term.

到上學(xué)期末我們已經(jīng)學(xué)了5000個(gè)英語(yǔ)單詞。

They had done the work at five o’clock.

在五點(diǎn)鐘的時(shí)候他們已經(jīng)完成了那項(xiàng)工作。