Grammar.

Conditionals.

Conditionals are situations or sentences that have a result. Those sentences as the name says are conditioned, therefore if a situation occurs there will be a consequence. Normally is used the preposition if or when.

There are four types of conditionals. I will explain one by one:

The first is the zero conditional: it is about real situations. Time in this case is used in the present; therefore the simple present is used.

Then the first conditional: it is a real or potential situation. In this case we need use one sentence in simple present and the other in simple future.

The second conditional: it refers to a hypothetical situation or unreal situation. It is necessary use simple past and present conditional or present continuous conditional.

And the third conditional: It refers about a situation in past and unreal situation. It is used past perfect and perfect conditional.

https://www.ego4u.com/en/cram-up/tests/conditional-sentences-3 

Simple past.



The simple past is used to actions that occur in the past and it finished in the past too. It is very easy to use and it is only of practice.

We have regular verbs in where we only add ed, and irregular verbs in where we need to change all the verb.

 

When the sentence is negative the correct form of create the sentence, it is use the word did.

In the next image could be give a clear idea to how use this verbal tense.

 

Finally, I upload a list with irregular verbs and their past tense.

http://www.englishpage.com/irregularverbs/irregularverbs.html



Past perfect.

The past perfect serves to indicate an action that happened before another, ie, the time before the recent past. It is composed of two parts: the past of the verb to have and the past participle of the principal verb.

 

Some examples are:

Mary had saved the document.

Mary had not saved the document.

Had she saved the document?

 

We can see that in the past examples one it is affirmative, the other negative and the last one it is a example to how formulate a question.

I found a excelent practice with this topic, and I wanted to upload it and share it. 

http://www.perfect-english-grammar.com/past-perfect-exercise-1.html 

 

Present perfect.

We use the present perfect when a action started in the past, but yet continued in the present. 

The Present Perfect Tense is formed using the following structure:
Affirmative: Subject + Have / Has + Past Participle
Negative: Subject + Haven't / Hasn't + Past Participle
Question: Have / Has + Subject + Past Participle
It is important remembered that we use has with he, she and it; and have with I, you, we and they.

 

http://www.really-learn-english.com/present-perfect-exercises.html