1. Overview:
The verbs "have," "has," and "had" can be both main verbs and auxiliary verbs. As main verbs, they show possession or ownership. As auxiliary verbs, they help form perfect tenses.
2. Cases of Usage:
Case 1: "Have" and "has" as main verbs show possession in the present.
Example: "I have a car." / "She has a bike."
Case 2: "Had" as a main verb shows possession in the past.
Example: "They had a house."
Case 3: "Have" and "has" as auxiliary verbs form the present perfect tense.
Example: "I have finished my homework." / "He has eaten lunch."
Case 4: "Had" as an auxiliary verb forms the past perfect tense.
Example: "She had left before I arrived."
3. Exceptions or Things to Pay Attention To:
When using "have" or "has" as a main verb, remember that "have" is used with I, you, we, they, and "has" is used with he, she, it.
Example: "I have a dog." (correct) vs. "He have a dog." (incorrect)
In negative sentences, "have" and "has" change to "don't have" and "doesn't have."
Example: "I don't have any money." / "She doesn't have a car."
4. Additional Notes:
When asking questions or making negatives, we use "do" or "does" with "have" as a main verb.
Example: Do you have a bike? / She does not have a bike.
When making questions or negatives with "have", "has" or "had" as auxiliary verbs, we need to place them before the subject.
Examples: Has he responded yet? Had you finished the project?
