Those tenses:(

Guess what people answer when asked why they think English is difficult. I bet everyone knew the answer before my not too long sentence ended. Yes, almost everyone says that the worst thing under the Sun to learn is English tenses.
Then they repeat terrifying legends about the number of English tenses. Some people say there are 12 tenses, some that there are 24 of them. I met a student who was trying to convince me that you don't need any tenses to communicate. So what is the truth? And are those horrid tenses really so hard to understand and learn?
In my opinion there are things to be much more afraid of (English-language-wise ofc) than tenses, which are all consistent and once you understand how they work, they aren't difficult anymore. Of course I don't promise you you won't need to learn them. On the contrary - if you want to use tenses correctly, you need a lot of practice. Remember you are Polish so you don't use English for everyday communication, you need a special training for your L2  (second language) skills.
Now, about the exact number of tenses. During my University studies I learned that we can talk about one real tense - the Present Simple. All the others are simply certain verb forms. Well, Present Simple is the most important tense, no doubt about it. You need to be able to operate it without any difficulties. This tense you use to talk about your life, your emotions, likes and dislikes. This tense tells about everyday life, habits and traditions. Sheryl Howard Pociecha in her book "Patchwork which is English" says that if you are able to use the Present Simple, you can talk about everything. Even a sentence like "I eat breakfast yesterday" can be understood. I don't encourage you though to learn only this one. You want to sound natural when you use a language and you want to express precisely your thoughts. For this you certainly need more than just Present Simple.
When I was my students' age, I was taught  that there are 32 English tenses! Dreadful news.... I suddenly felt overwhelmed, unable to even dream about ever knowing English well enough to communicate. But then, gradually I discovered that it isn't that hard, and I'll try to explain to you how I understood English tenses.
Let's think about what we need to communicate with people. We need to talk to them about present, past and future time. We want to tell them about our life, our regular actions, likes and dislikes, our habits and traditions, and, of course about what we are doing at present. All these refer to the present time. Sometimes we need to talk about our plans and intentions. We want to share our predictions or dreams about the future too. It means we need to be able to talk about future time. We often need to tell our friends about our adventures or experiences we had. We want to talk about past actions, things that happened in past time. Here you are three dimensions of our reality:

PRESENT    >>>>     PAST    >>>    FUTURE

I am sure you understand this - in our language we also use tenses referring to present, past and future time.


Now, another concept. We have actions which are in progress, happening at certain time. We say:

I am reading a book.
She is cooking dinner.
They were  watching TV yesterday at eight o'clock.
Mary and John will be arriving in London tomorrow at 5pm.

The above sentences show actions in progress. We don't know when they started or ended. All those tenses are Continuous.

Another group of tenses tell us about actions that happened before the time we are talking about, but they are all connected with that time:

I have read many fantasy books. (I did it in the past, now I know what they are about, and I will read fantasy books again in the future)

She had started cooking dinner before Darren arrived. (we state time in the past = Darren arrived; before he did she had already started cooking )


They will have finished building the bridge by May 2016. (we state time in the future = May 2016; before that time the bridge will be ready)

All those actions happened before the time we were talking about and all of them were connected with that time. All those tenses are Perfect.

Simple tenses are the most general, it means that firstly, they all belong to the time they talk about, secondly they tell about complete activities , feelings, emotions etc.

Uncle Ben likes sitting outside with his pipe.(likes)

Mary visits her Grandma every Friday evening.(action repeated regularly)

Sean met his girlfriend at the summer camp. (stated time in the past)

They never ate mushroom when they were little. (stated time in the past)

Humans will live on Mars in 200 years. (prediction based on what I think)

Sometimes Perfect and Continues tenses join to show duration of an activity.

He's been reading since morning. (it is afternoon now and I can see him reading all the time)

Lucy had been watching TV for 3 hours when her mother came back from work. (naughty Lucy, she wasted 3 hours watching TV before her mum arrived)

Here you are a video that may help you understand a difference between  Simple Past, Simple Present and Present Perfect.