Stop! Grammar time.

Tense. Yes, you may feel this way when it comes to writing, whether informally or formally (for work or educational purposes). But 'tense' is also important for understanding what people are talking or writing about: whether it is in the past, present or future.

Tense takes a base word (basically any word in the dictionary) and changes its ending so either a listener or reader understands the time period someone is writing or speaking about.

Cleary, B. P and Lew-Vriethoff, J. (2010).

This resource can be found 

So, take an example like the word tolerate. As the image above shows, this word will change its ending to show its tense.

• Mike tolerates Mitchell : This is the present tense for third person use. Because you can switch 'Mike' for 'he' and the sentence still makes sense, the present tense is used and the -s is added to the end.

• Mike thought he was tolerating Mitchell well :  This is the present tense for first or second person use. In the sentence, 'Mike thought' shows his internal monologue and perspective, suggesting that for present tense -ing is added to the end of the word.

• Mike had tolerated Mitchell for long enough : This is the past tense of the word and can be used for first, second or third person writing. The sentence shows Mike has been around Mitchell in the past, for possibly a long time, and has found he can no longer take what Mitchell is like anymore. To show the past relationship; therefore, -ed is added to the end of the word. 

These are past, present and future 'simple' tense examples. That doesn't mean it is always easy to stay consistent and clear in your writing though, particularly for essays.

Whilst you can write past and present tense in essays at the same time:

Smith argues that ...

Smith has argued that ...

You want to make sure that the work is consistent, clear and makes sense before you hand it in. 

As seen above, mixing tenses can also add a lot more depth to creative writing pieces. You just need to make sure your time periods and phrasing work well with each other.

The best way to know if a paragraph or sentence is working the right way for essays or stories? Rewrite them using different tenses! Then you get some well-worn practice in and you will see which works better for the point or plot you are creating.