Present simple

We use the present simple to talk about actions we see as long term or permanent. It is a very common and very important tense.
Here, we are talking about regular actions or events.

• They drive to the office every day.
  
• She doesn't come here very often.
  
• The news usually starts at 6.00 every evening.
  
• Do you usually have bacon and eggs for breakfast?
  

Here, we are talking about facts.

• We have two children.
  
• Water freezes at 0° C or 32° F.
  
• What does this expression mean?
  
• The Thames flows through London.
  

Here, we are talking about future facts, usually found in a timetable or a chart.

• Christmas Day falls on a Monday this year.
  
• The plane leaves at 5.00 tomorrow morning.
  
• Ramadan doesn't start for another 3 weeks.
  
• Does the class begin at 10 or 11 this week?
  

Here, we are talking about our thoughts and feelings at the time of speaking. Although these feelings can be short-term, we use the present simple and not the present continuous.

• They don't ever agree with us.
  
• I think you are right.
  
• She doesn't want you to do it.
  
• Do you understand what I am trying to say.
  

http://www.englishgrammarsecrets.com/presentsimple/menu.php