SIMPLE PAST
http://www.aprenderinglesfacil.es/2008/04/pasado-simple-simple-past-tense.html

Going to or will

When we want to talk about future facts or things we believe to be true about the future, we use 'will'.

• The President will serve for four years.
• The boss won't be very happy.
• I'm sure you'll like her.
• I'm certain he'll do a good job.

If we are not so certain about the future, we use 'will' with expressions such as 'probably', 'possibly', 'I think', 'I hope'.

• I hope you'll visit me in my home one day.
• She'll probably be a great success.
• I'll possibly come but I may not get back in time.
• I think we'll get on well.

If you are making a future prediction based on evidence in the present situation, use 'going to'.

• Not a cloud in the sky. It's going to be another warm day.
• Look at the queue. We're not going to get in for hours.
• The traffic is terrible. We're going to miss our flight.
• Be careful! You're going to spill your coffee.

At the moment of making a decision, use 'will'. Once you have made the decision, talk about it using 'going to'.

• I'll call Jenny to let her know. Sarah, I need Jenny's number. I'm going to call her about the meeting.
• I'll come and have a drink with you but I must let Harry know. Harry, I'm going to have a drink with Simon.

SIMPLE PRESENT
http://www.inglessencillo.com/presente-simple

CONDITIONAL 0

use: to express a general truth or a scientific fact. in this type of conditional, we can use when instead of if.
when the if-clause precedes tha main clause, we use a comma to separate the two clauses.

conversation

Alfredo: Hello. My name is Alfredo. 

George: Hello Alfredo, I'm George.
 George: How can I help you?
 Alfredo: Can you tell me where Shinra Factory is?
 George: I'm sorry. I have no idea. You're not from here right? 
Alfredo: I've just arrived. I'm from Spain. 
George: I see. What brings you here to London? 
Alfredo: Business.
 George: Well, I'm sorry I can't help you with that. Maybe that cop can help you.
 Alfredo: I'll go ask him. Thank you. George: No problem. If you need any help, I'm here every day. 
Alfredo: It was nice to meet you. Catch you later George: See you, and good luck.

simple past

+

I went

you went

he went

she went

it went

we went

you went

they went

_

I didn't

you didn't

he didn't

she didn't

it didn't

we didn't

you didn't

they didn't

?

did I?

did you?

did he?

did she?

did it?

did we?

did you?

did they?

simple present

+

I go

you go

he goes

she goes

it goes

we go

you go

they go

_

I don't go

you don't go

he doesn't go

she doesn't go

it doesn't go

we don't go

you don't go

they don't go

?

do I go?

do you go?

does he go?

does she go?

does it go?

do we go?

do you go?

do they go?