I have worked (present perfect)

POSITIVE:  I / They / We / You + HAVE + worked / eaten (Past Participle)

He / She / It + HAS + worked / eaten (Past Participle)

NEGATIVE:  I / They / We / You + HAVE NOT (haven’t) + worked / eaten (Past Participle)

He / She / It + HAS NOT (hasn’t) + worked / eaten (Past Participle)

QUESTION:  HAVE + I / They / We / You + worked / eaten (Past Participle) ? 

HAS + He / She / It + HAS NOT (hasn’t) + worked / eaten (Past Participle)? 

For Example,

I have already taken a bath. 

She has worked in that company before. 

They haven’t met my boyfriend. 

I haven’t had dinner yet. 

Have you submitted the report? 

USES: 

UNFINISHED ACTIONS

We use the present perfect when we want to talk about unfinished actions that started in the past and continue to the present. We usually need ‘since’ or ‘for’. We often use stative verbs. 

For example,

She has known her since 2005. 

I have lived in Spain for five years. 

FOR and SINCE for TIME

We have lived there for ten years. 

My best friend has been on vacation since Monday. 

FOR + Period: a “period” is a duration of time; means from the beginning of the period to the end of the period. 

for 20 minutes 

for three days 

for six months 

for 4 years 

for a long time 

SINCE + Point: a “point” is a precise moment of time; means from a point in the past until now. 

since 9 AM

since Monday

since January

since 1998

since I was young 

since I left school/work

FINISHED ACTIONS

Life experience. These are actions that happened sometime during a person’s life, and the person needs to be alive now. 

For example,

She has been to Spain. 

I have visited Israel before. 

With an unfinished time word (this month, this week, today). The period of time is still continuing. 

For example,

I haven’t eaten any junk food this week. 

She has drunk five cups of coffee today. 

A finished action with a result in the present (focus on the result.) 

For example,

I have exercised hard this year. (so I am fit)

She has lost her keys. (so she can’t get into her house)