Could: Form and Use /Lesson

Could


Could is an auxiliary verb, a modal auxiliary verb. We use could to:

• talk about past possibility or ability
  
• make requests
  

Structure of Could


subject + could + main verb
The main verb is always the bare infinitive (infinitive without "to").

	subject	auxiliary verb	main verb
+	My grandmother	could	swim.
-	She	could not	walk.
		couldn't
?	Could	your grandmother	swim?

Notice that:

• Could is invariable. There is only one form of could.
  
• The main verb is always the bare infinitive.
  

The main verb is always the bare infinitive. We cannot say: Fatima could to cook.

Use of Could


could: Past Possibility or Ability


We use could to talk about what was possible in the past, what we were able or free to do:

• I could swim when I was 5 years old.
  
• My grandfather could speak three languages.
  
• When we arrived home, we could not open the door. (...couldn't open the door.)
  
• Could you understand what he was saying?
  

We use could (positive) and couldn't (negative) for general ability in the past. But when we talk about one special occasion in the past, we use be able to (positive) and couldn't (negative). Look at these examples:

	Past
	General	Specific Occasion
+	My mother could speak Spanish.	A man fell into the river yesterday. The police were able to save him.
-	My mother couldn't speak Spanish.	A man fell into the river yesterday. The police couldn't save him.

could: Requests


We often use could in a question to ask somebody to do something. The use of could in this way is fairly polite (formal):

• Could you tell me where the bank is, please?
  
• Could you send me a catalogue, please?