Topic: Verbs: Perfect Tenses

Day 4: Simple Past Tense and Present Perfect Tense

Q4: What is the difference between ‘I broke it yesterday’ and ‘I have broken it’?

The simple past tense and present perfect tense are two easily confused tenses.

簡單過去式與現在完成式是兩種容易混淆的時態。

l The present perfect tense is formed by have/has + past participle. For the simple past tense, we use the past tense form of the verb. In questions and negative statements in the simple past tense, we use the verb did.
現在進行式是由 have/has 與過去分詞組成的。在過去式中我們會用動詞的過去式。在過去式的問句和否定句中，我們會用到動詞 did。

Simple past:

He sent Mary a letter last week.

Did he send Mary a letter last week?

Yes, he did.

No, he didn’t.

Present perfect:

He has sent Mary a letter.

Has he sent Mary a letter?

Yes, he has.

No, he hasn’t.

l We often use the present perfect tense to talk about past actions with unknown past time. We cannot use adverbs of time such as yesterday, last week, a long time ago, in the old days, etc, which we use with the simple past tense. If we know the time when the past action happened, we use the simple past tense.
我們把現在進行式用在不清楚時間的過去事情上。我們不能用在過去式常用的時間副詞?A如yesterday, last week, a long time ago, in the old days 等。如果我們知道那件過去事情發生的時間，我們會用過去式。

Present perfect:

He has returned from Japan.

→We know that the time he returned was in the past, but we do not know the time, or we do not want to state the time.

Simple past:

He returned from Japan last weekend.

→We know the time in past when he returned.