Simple Past – Present Perfect Simple

Form

Simple Past	Present Perfect Simple
irregular verbs: see 2nd column of irregular verbs Example: I spoke	irregular verbs: form of 'have' + 3rd column of irregular verbs Example: I / you / we / they have spoken he / she / it has spoken
regular verbs: infinitive + ed Example: I worked	regular verbs: form of 'have' + infinitive + ed Example: I / you / we / they have worked he / she / it has worked
Exceptions
Exceptions when adding 'ed': when the final letter is e, only add d Example: love - loved after a short, stressed vowel, the final consonant is doubled Example: admit - admitted final l is always doubled in British English (not in American English) Example: travel - travelled after a consonant, final y becomes i (but: not after a vowel) Example: worry - worried but: play - played

See also explanations on Simple Past and Present Perfect Simple

Use

In British English, the use of Simple Past and Present Perfect is quite strict. As soon as a time expression in the past is given, you have to use Simple Past. If there are no signal words, you must decide if we just talk about an action in the past or if its consequence in the present is important.

Note that the following explanations and exercises refer to British English only. In American English, you can normally use Simple Past instead of Present Perfect. We cannot accept this in our exercises, however, as this would lead to confusions amongst those who have to learn the differences.

Certain time in the past or just / already / yet?

Do you want to express that an action happened at a certain time in the past (even if it was just a few seconds ago) or that an action has just / already / not yet happened?

Simple Past	Present Perfect Simple
certain time in the past Example: I phoned Mary 2 minutes ago.	just / already / not yet Example: I have just phoned Mary.

Certain event in the past or how often so far?

Do you want to express when a certain action took place or whether / how often an action has happened till now?

Simple Past	Present Perfect Simple
certain event in the past Example: He went to Canada last summer.	whether / how often till now Example: Have you ever been to Canada? / I have been to Canada twice.

Emphasis on action or result?

Do you just want to express what happened in the past? Or do you want to emphasise the result (a past action's consequence in the present)?

Simple Past	Present Perfect Simple
Emphasis on action Example: I bought a new bike. (just telling what I did in the past.)	Emphasis on result Example: I have bought a new bike. (With this sentence I actually want to express that I have a new bike now.)

Signal Words

Simple Past	Present Perfect Simple
yesterday ... ago in 1990 the other day last ...	just already up to now until now / till now ever (not) yet so far lately / recently

FAÇA OS TESTES NO SITE: http://www.ego4u.com/en/cram-up/grammar/simpas-preper