Use the simple present to express a regular or repeated action:
-I write articles.
-He drives to his brother's house every Saturday.
-They play piano.
A speaker also uses the simple present to state a fact or generalization he believes to be true in the past, present and future.
-Children love candy.
-Paris is in France.
-All dogs bite.
The simple present can also indicate events in the near future scheduled to take place at a certain time.
-The plane leaves at 4:00.
-I arrive at 8:00.
-We come home tomorrow evening.
When used with non-continuous verbs, the simple present can express an action that is happening now.
-Sheila is at school.
-I need water.
-You have the keys.
To express an action or series of actions completed at a specific point in the past, use the simple past tense.
-I spoke to your father last month.
-We walked the dog an hour ago.
-You took your English exam, turned it in, and then went to the party.
A duration is a continuous action that begins, spans a period of time, and ends in the past.
-She lived in Europe for six months.
-I ran on the treadmill for an hour.
-They waited all night.
The simple past can express an action that was regular and repeated in the past, but no longer is so. This use of the simple past can also be conveyed with the term "used to."
-Wendy fed the cat every day when she lived here.
-I wanted a pet rhinoceros when I was a child.
-We played football in high school.