Page 132 - DENG102_COMMUNICATION_SKILLS_II

Unit 9: Tenses

9.4 modal auxiliary verbs notes

Modal auxiliary verbs are those verbs that qualify the “mood” of the verb they “help.”

9.4.1 could

Could is a modal auxiliary verb and is used to:

1. talk about past possibility or ability
2. make requests
Structure: subject + could + main verb
The main verb is always the bare infinitive (infinitive without “to”).

subject auxiliary verb main verb
Positive My last dog could swim.
negative My last dog could not/couldn’t walk.
interrogative could your last dog swim?

Notes could is invariable. There is only one form of could.

The main verb is always the bare infinitive.

use of could

1. Past Possibility or Ability: We use could to talk about what was possible in the past, what
we were able or free to do:
(a) I could sing when I was 1 year old.
(b) My great grandmother could speak five languages.

(c) When we arrived home, we could not open the door. (...couldn’t open the door.)
(d) could you understand what he was trying to say?
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

Positive My grandmother could speak Latin. A boy fell into a well yesterday. The
military were able to save him.
negative My grandmother couldn’t speak Hindi. A boy fell into a well river yesterday.
The military couldn’t save him.
2. 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):
(a) could you please tell me where the bus stand is?
(b) could you send me an e-mail, please?

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