The word can has three parts of speech in English: modal verbs, nouns, and verbs. They vary in meaning and usage and need to be distinguished according to the context. Below I will introduce the usage of each of these three parts of speech, and give some example sentences and extended content.
One, can as a modal verb.
1, can as a modal verb, when used as a modal verb, denotes concepts such as capacity, permission, request, possibility, etc. It is usually followed by a verb primitive, forming the structure of can + verb primitive. For example:
i can speak three languages.I speak three languages. (Indicates ability).
you can use my computer.You can use my computer. (Indicates Permission).
can you help me with this problem?Can you help me with this? (Indicates Request).
it can rain tomorrow.Tomorrow it may rain. (indicates the possibility).
2. When can is used as a modal verb, there are the following points to pay attention to:
can is used without the change of pronoun and number, regardless of whether the subject is singular or plural. For example:
she can play the piano.She can play the piano.
they can play the piano.They can play the piano.
Can has no change in tense and is used to indicate that the past tense is to be could, and the future tense is to be able to or the ing form of can + verb. For example:
i could swim when i was five.I could swim when I was five years old. (denotes past tense).
i will be able to swim next year.I'll be swimming next year. (denotes future tense).
i can't go out now. i'm doing my homework.I can't go out right now. I'm doing my homework. (indicates present continuous tense).
The negative form of can is can't or cannot, which means that it cannot or will not. For example:
i can't see anything. it's too dark.I can't see anything. It's too dark.
you cannot smoke here. it's forbidden.You can't smoke here. This is forbidden.
The interrogative form of can is to put can at the beginning of the sentence, indicating the ability to ask, permission, request, possibility, etc. For example:
can you drive a car?Do you know how to drive? (Ability to ask).
can i borrow your book?Can I borrow your books? (Ask for permission).
can you pass me the salt?Can you hand me the salt? (Ask Request).
can it be true?Could this be true? (Ask about the possibility).
Second, can as a noun.
1. Can, when used as a noun, usually refers to a metal can or a canned quantity that holds food or drink. For example:
a can of coke.
a can of soup.
a can opener.
2. When can is used as a noun, it can also refer to metal or plastic containers used to transport liquids, such as watering cans, oil drums, etc. For example:
a watering can watering can.
a petrol can oil drum.
a spray can spray can.
3, can as a noun, is a countable noun, in singular and plural forms. For example:
he bought two cans of beer.He bought two cans of beer.
there are many empty cans in the bin.There are a lot of empty cans in the trash.
Three, can as a verb.
1, can as a verb, is a transitive verb that means to keep food or drink in cans. For example:
they can tomatoes every summer.They canned the tomatoes every summer.
you can buy canned fish in the supermarket.You can buy canned fish in supermarkets.
2, when can as a verb, in North American English, there is also an informal usage to denote dismissal or expulsion. For example:
he was canned for stealing money from the company.He was fired for stealing money from the company.
she canned her assistant for being lazy.She fired her because her assistant was lazy.
Learning the parts of speech and usage of can not only improve English proficiency, but also increase the richness and flexibility of English expressions. Thank you for reading!