The present perfect is used to talk about an action that happened at a time before now, but it is not specified when it happened because it doesn’t have relevance. Sometimes, we want to limit the time we are refering to by using expressions such as in the last week, in the last year, this week, this month, so far, up to now, etc. We can also use the Present Perfect to show that something started in the past and has continued up until now (“For two hours,” “for three days,” or “since Saturday”), with the use of non-continuous Verbs and non-continuous uses of mixed verbs.
Simple future has two different forms in English: will and going to. Although both forms can sometimes be used interchangeably, they often express two very different meanings. Both forms refer to specific time in future.
** REMEMBER: We should conjugate the verb be according to the subject.
Negative sentences structure: Subject + [be not going to + verb] + complement
Examples:
I am not going to send a letter tomorrow
We aren’t going to perform a song tonight.
Yes/No questions structure: Be + subject + going to verb + complement + ?
Examples:
Are you going to send a letter tomorrow?
Affirmative: Yes, I am
Negative: No, I am not
Wh-questions structure: Wh-word (what, which, when…) + Be + subject + going to verb + complement + ?
Examples:
What are you going to send tomorrow? A: I’m going to send a letter tomorrow
Uses
USE 1 “Will” to Express a Voluntary Action
“Will” often suggests that a speaker will do something voluntarily. A voluntary action is one the speaker offers to do for someone else.
Examples:
I will paint your wall if you need it.
She will translate the Japanese text, so Mr. Baratheon can read it.
I won’t help Mary because she was very mean with me.
A: I’m really hungry
B: I’ll make some sandwiches
USE 2 “Will” to Express a Promise
Examples:
I will give you a beautiful gift for Christmas
If I win the elections the next year, I will solve poverty in Costa Rica
You won’t tell anyone my secret, right?
USE 3 “Be going to” to express a Plan/Arrangement
“Be going to” expresses that something is a plan. It expresses the idea that a person intends to do something in the future. It does not matter whether the plan is realistic or not.
Examples:
He is going to meet the president next Wednesday.
I am going to spend my vacation in Russia.
Are you going to invite Cersei to the party tonight?
I’m not going to be an actor when I grow up.
USE 4 “Will” or “Be Going to” to Express a Prediction
Both “will” and “be going to” can express the idea of a general prediction about the future. Predictions are guesses about what might happen in the future.
Examples:
In the year 5894, a post-human race will invade the planet
In the year 5894, a post-human race is going to invade the planet
If we add an “if”, it is mandatory to use will.
I don’t know if Oscar Arias will win the elections in 2018
USE 5 “Going to” to express something that is likely to happen
Be careful! You are going to fall
Look at those hungry lions. I think they are going to bite our bodies