Module 4: Mastering Modal Verbs - Lesson 4.2: Modal Verbs of Ability: CAN and COULD

Module 4: Mastering Modal Verbs - Lesson 4.2: Modal Verbs of Ability: CAN and COULD

Lesson 4.2: Modal Verbs of Ability - CAN and COULD

In this lesson, we will focus on two fundamental modal verbs that express ability in English: CAN and COULD. These modals are used to indicate what someone or something is able to do, either in the present or the past. Understanding and using CAN and COULD correctly is crucial for expressing competence, skills, and possibilities related to ability.

CAN - Expressing Present Ability

CAN is the modal verb used to express present ability. It indicates that someone has the skill, capacity, or permission to do something *now* or in general.

Key Uses of CAN (Ability):

  • General Ability in the Present: To say that someone knows how to do something or has the general capacity to do it.
  • Specific Ability in the Present Situation: To say that someone is able to do something in a particular situation at the present time.
  • Possibility (Informal): "Can" can sometimes be used to express general possibility, especially in informal contexts, although "may" and "might" are more common for possibility. (We will focus on ability in this lesson and explore possibility later).

Forming Sentences with CAN (Ability):

The structure is simple:

Formula: Subject + can + Base Verb

Examples of CAN (Ability) in Use:

  • General Ability in the Present:
    • "I can speak English and Spanish." (General skill - knows how to speak languages)
    • "Birds can fly." (General ability of birds - inherent capacity)
    • "She can play the piano very well." (General skill - has musical ability)
    • "He can swim fast." (General skill - athletic ability)
    • "They can cook delicious meals." (General skill - culinary ability)
  • Specific Ability in the Present Situation:
    • "Can you help me with this heavy box?" (Ability to assist in this specific situation - request for help)
    • "I'm sorry, I can't come to the party tonight." (Lack of ability in this specific situation - inability to attend)
    • "Can you hear me clearly?" (Ability to perceive sound in the current situation - checking audibility)
    • "Can we park here?" (Ability to perform an action in this location - asking about parking possibility/permission implied)
    • "She can finish the project by tomorrow." (Belief in her ability to complete task within a timeframe)

Negative and Question Forms of CAN (Ability):

For negative and question forms with "can," we simply adjust "can":

  • Negative: Subject + cannot / can't + Base Verb (e.g., I cannot swim, She can't play) - Contraction: *can't* is very common in spoken and informal written English. *Cannot* is used in more formal writing.
  • Question: Can + Subject + Base Verb? (e.g., Can you swim? Can she play?)

Examples of Negative and Question Forms with CAN:

  • "I cannot understand this problem." / "I can't understand this problem." (Lack of present ability - inability to comprehend)
  • "He cannot drive a car." / "He can't drive a car." (Lack of general ability - inability to drive)
  • "They cannot come to the meeting." / "They can't come to the meeting." (Inability in a specific situation - unable to attend)
  • "Can you speak louder, please?" (Question about ability - request to speak louder)
  • "Can she see without her glasses?" (Question about ability - checking visual ability)
  • "What can I do to help?" (Question about ability - asking about possible actions)

COULD - Expressing Past Ability (and Polite Possibilities/Requests - Later Lessons)

COULD is the modal verb primarily used to express past ability. It indicates that someone had the skill or capacity to do something in the past, but it doesn't necessarily mean they still have that ability now. "Could" also has other uses (possibility, polite requests/suggestions) which we will explore in later lessons. In this lesson, we focus on its use for past ability.

Key Uses of COULD (Past Ability):

  • General Ability in the Past: To say that someone knew how to do something or had the general capacity to do it in the past.
  • Specific Ability in a Past Situation: To say that someone was able to do something in a particular situation in the past.

Forming Sentences with COULD (Past Ability):

The structure is:

Formula: Subject + could + Base Verb

Examples of COULD (Past Ability) in Use:

  • General Ability in the Past:
    • "When I was younger, I could run very fast." (Past general ability - athletic ability in the past, may not be true now)
    • "She could play the violin beautifully when she was a child." (Past general skill - musical ability in childhood)
    • "He could speak French fluently when he lived in Paris." (Past general skill - language ability during a specific period)
    • "They could swim across the lake when they were teenagers." (Past general ability - physical ability in youth)
  • Specific Ability in a Past Situation:
    • "I couldn't sleep last night because of the noise." (Lack of ability in a specific past situation - inability to sleep last night)
    • "She could finish