Use of Can and Can't

 Use of Can and Can't

With the modal verb can and can't in English, we come to the favorite topic of all motivational speakers, who say things like “yes, we can”.

When to Use the Modal Verb "Can" and "Can't" in English?

The most basic use of "can" and "can't" is to express skills. If we can draw, we will say:

I can draw

If, on the other hand, we cannot cook and we are burned to the water, we can say:

I can't cook / I can't cook

That is, we use "can" to express that we have the ability to do something and "can't" to say that we do not have the ability to do it. Let's look at some examples from the animal world:

• Birds can fly / las aves pueden volar
• Dolphins can swim / los delfines pueden nadar
• Penguins can’t fly / los pingüinos no pueden volar
• Monkeys can walk / los monos pueden caminar
• Fish can’t run / los peces no pueden correr

Other Uses of Can and Can't

We could also use "can" to say we're willing to do something, and "can't" when we don't have availability. These expressions are useful to offer us to collaborate in some task, or the opposite: to present excuses and say that we will not be available for it.

• Are you having trouble with your homework? I can help you with that

¿Estás teniendo problemas con tu tarea? Yo puedo ayudarte con eso

• I am sorry, but I can’t help you with the decoration / Disculpame, pero no puedo ayudarte con la decoración

And in general, we use can to make offers, such as:

• How can I help you? / ¿Cómo puedo ayudarle?

This is a classic phrase from the world of customer service. We also use "can" to ask permission or talk about limits and rules:

• an I go to the party, mom? / Puedo ir a la fiesta mamá?

• He can’t have a dog, Tom. He is too young / No puede tener un perro, Tom. Es demasiado joven.

• You can go, but you can’t stay out late / Puedes ir, pero no te puedes quedar afuera hasta tarde.

Finally, there is the use of "can" and "can't" to talk about facts and trends, for example:

• If a child feels rejected, she can develop a rebellious attitude / Si un niño se siente rechazado, puede desarrollar una actitud rebelde.

• Rain can cause floods in areas with poor drainage / La lluvia puede causar inundaciones en áreas con mal drenaje.

¿ How to Use the Modal Verb "Can" and "Can't" in English?

The use of "can" is very simple: this is a modal, that is, it does not conjugate (although it does have a different modality in the past and in the future, which we will see later in this article). To construct positive phrases, we add "can" between the subject and the verb:

• My mother can make homemade pasta / Mi mamá puede preparar pasta casera

• She can help you clean up after the party / Ella te puede ayudar a limpiar después de la fiesta

To construct negative sentences, we add "can't" between the subject and the verb:

• Grandpa can’t hear you / El abuelo no te puede escuchar

• This dog can’t stand still  / Este perro no se puede quedar tranquilo

Another way to say "can't" is "cannot"; we use this when we want to be emphatic:

• I cannot believe she said that! / ¡No puedo creer que ella dijo eso!

To ask questions, we start with "can", like this:

• Can you drive a truck? / ¿Puedes manejar un camión?

To make offers, we also start with "can":

- Can I take your coat?

And if we want to make it even more formal and polite, we use "could":

- Could I get you some dessert?

"Can" and "Can't" in the Past and Future

This is one of the topics that most confuses students, but we have good news: the truth is that it is super easy. When we want to use "can" to talk about the future, the expression we need is "will be able":

- I will be able to speak English like a native in a couple of years /  Seré capaz de hablar inglés como un nativo en un par de años

And if we wanted to use it for negative phrases, we simply say will not = won't; won't be able to.

- Sorry, I won't be able to join you tonight

To use "can" and "can't" in the past, the correct expression is "could"

- I couldn't finish the homework in time

- When I was younger, I could stay up all night reading

NOTE: We don't say "will can", or "won't can" for the future, or "canted" for the past