Today we know about exposition can, could and be able to, to aditional examples such as:


we have some examples about could:

• You could be wrong.
  Podrías estar equivocado.
• They could manage without us.
  Ellos pudieron/podrían arreglárselas sin nosotros.
• I could help Ann if she only let me.
  Yo podría ayudar a Ann si tan solo me dejara.
• This new plan could be very risky.
  Este nuevo plan podría ser muy riesgoso.
• The news could kill Mr. Taylor.
  La noticia podría matarlo al señor Taylor.
• Anybody could be chosen for the job.
  Cualquiera podría ser elegido para el trabajo.
• I could go back and bring Kate with me.
  Yo podría/pude volver y traer a Kate conmigo. 

some examples about can:

• She can drive a car.
• John can speak Spanish.
• I cannot hear you. (I can't hear you.)
• Can you hear me?

some examples about be able to:

• I was able to drive...
• I will be able to drive...
• I have been able to drive...