Catch the pen
Get the bus
Take the bus
Catch the bus
But what about these sentences?
Get the pen
Take the pen
Catch the pen
I don't know why when I say "catch the pen" I think about something in movement. Is that it?
6 Answers
Get the pen, cógelo del salón.
take the pen, de la mesa
catch the pen, te lo tiro
Get the pen
The pen is located away from the speaker and she wants the other person to "get the pen."
Take the pen
The speaker is holding the pen and hands it to the other person, saying "Here, take the pen."
Catch the pen
The speaker throws the pen to the other person.
I had always thought that these three verbs were interchangeable on these contexts.
Yes, you're right. These three verbs (get, catch, and take) are interchangeable in this situation.
All of your sentences work 
Get the bus - what you would say to a bus driver - example: "Get the bus and drive your route."
Take the bus - what you would say to someone who rides the bus
Catch the bus - what you say to someone who needs to get on the bus
Get the pen
Take the pen
Catch the pen - example: "Catch the pen when I throw it"
Yes, you're right. These three verbs (get, catch, and take) are interchangeable in this situation.
Here in the U.S., the three are not interchangeable. "Get" would be different unless you said "get on" the bus.
Get the bus - what you would say to a bus driver - example: "Get the bus and drive your route."
Take the bus - what you would say to someone who rides the bus
Catch the bus - what you say to someone who needs to get on the bus
Really?. I had always thought that these three verbs were interchangeable on these contexts.
