Tenses in English can be divided into three groups - present, past and future. Within each group there are several variations of each tense, all of which serve a different purpose and require changes to the verb forms used. Perhaps one of the most common verb forms is the infinitive "to be": I am, you are, she is (present tense), I was, you were, she was (past tense) and so on. Let's look at the tenses in more detail.

Present simple (verb+ s/es in third person)

This is used to talk about the here-and-now, plus things done on a regular basis or preferences:

I am in the office. I walk to work. I read books. I like chocolate.

Present continuous (am/is/are + present participle)

You can use this tense to talk about the here-and-now as well as plans for the future. The "ing" form (gerund) of the verb is always used after the infinitive "to be":

I am reading a book - please be quiet. I am travelling to Scotland tomorrow.

Present perfect (has/have + past participle)

This tense is used to talk about experiences in our lives - what we have or haven't done. Here, the time when we did things is not important:

Have you ever travelled to Scotland? He has never liked chocolate. She has read the book.

Present perfect continuous (has/have + been + present participle)

We use this tense to show that something was started in the past and is still ongoing, that is, it hasn't finished yet. Note that a time scale (hours, days, weeks etc) is always included:

He has been travelling for five hours. She has been reading the book all day.

Past simple (verb +ed, also irregular verbs)

This shows what we did in the past: He walked to the office. She liked the book.

Past continuous (was/were + present participle)

This tense often "sets the scene" for recounting a story. We use it to describe an action that took place at a specific period of time. It is often joined with "while" or "when":

I was watching television when he called. I was reading a book while he cooked dinner.

Past perfect (had + past participle)

We use this tense to talk about an action that had been carried out in the past prior to another past action:

I missed the bus because it had left early. I wasn't hungry - I had eaten at home.

Past perfect continuous (had been + present participle)

This tense describes something that began in the past and continued up until another point of time in the past:

They had been waiting over an hour for the bus when it finally arrived.

Future simple (will + verb) and (am/is/are + going to + verb)

We normally use either "will" or "be going to" in this tense, both of which talk about a task being carried out at a specific time in the future:

I will travel to Scotland tomorrow. I am going to travel to Scotland tomorrow.

Future continuous (will be + present participle) and (am/is/are + going to be + present participle)

We use this tense to show that a longer action in the future will be interrupted by a shorter action, also taking place in the future. This can be an actual interruption or an interruption in time. This tense also has two different forms:

I will be waiting for you when you arrive in Scotland tomorrow. I am going to be travelling all day tomorrow.

Future perfect (will have + past participle) and (am/is/are + going to have + past participle)

This tense states the idea that something will happen before another action in the future. It can also show that something will occur before a certain time in the future. Once again, there are two forms:

You will have travelled for many hours by the time I meet you in Scotland. I am going to have waited for hours by the time your plane lands.

Future perfect continuous (will have been + present participle) and (am/is/are + going to have been + present participle)

This tense is used to show that something will continue up until a specific event or time in the future. "For ten minutes," "for three weeks," and "since Tuesday" are all durations in time which can be used with this tense.

KJ Hutchings is the owner of KJ Language Services, providing proofreading, editing and writing services to businesses and students, in particular those who use English as a second language. For more information, visit her site at: http://www.kjlanguageservices.com/