How is the present perfect tense formed?

The present perfect tense is formed by using the auxiliary verb "have" or "has" followed by the past participle of the main verb. The auxiliary verb "have" is used with plural subjects (e.g., we, they, you) and the pronoun "I," while the auxiliary verb "has" is used with singular subjects (e.g., he, she, it) and singular nouns.

The past participle of regular verbs is formed by adding "-ed" to the base form of the verb. For example, the past participle of the verb "walk" is "walked." However, irregular verbs have different past participle forms that need to be memorized. For instance, the past participle of the verb "go" is "gone."

Here are some examples of sentences in the present perfect tense:

- I have studied for the exam.
- She has finished her work.
- They have traveled to many countries.
- He has eaten lunch already.
- We have seen that movie before.

In these examples, the auxiliary verb "have" or "has" is followed by the past participle of the main verb (e.g., studied, finished, traveled, eaten, seen), indicating that the action or state started in the past and is still relevant in the present.