Present tenses

We use present simple to express:

• a past action

• an action that happens repeatedly

• action according to timetables

• general truths

Present simple tense:

• Jane has been a teacher since 1999.

• Jane is Maths teacher.

Present continuous expresses:

• an action that is in progress at the time of speaking.

• an action that was in progress at a certain time in the past.

• an action that is annoying

• an action that is happening around the time of speaking.

Present continous:

• She was smiling at me.

• She is always leaving lights on.

Present perfect simple is used to express:

• an action that happened in the past but the time is not indicated.

• an action that has started in the past and still continues (especially when using state verbs).

• an action that is used with such time expressions as today, this morning, etc.

• an action in the past

Present perfect simple:

• I have already emailed it to the boss.

• I already emailed it to the boss.

Present perfect continuous expresses:

• the duration of an action which started in the past and still continues.

• started in the past and the result is visible now.

• an action in progress at a stated future time.

Present perfect continuous:

• Have you been trying hard enough?

• They will have arrived.