The verb "lay" is an irregular verb in English, used to describe the action of putting or placing something in a horizontal position. It follows a somewhat irregular pattern for conjugation, particularly in the past tense and past participle forms.

In the present simple tense, "lay" follows its base form for most subjects: "I lay," "you lay," "he/she/it lays," and so on. For example, "She lays the book on the table."

In the past simple tense, "lay" changes to "laid." This irregular form is used to describe the action of putting or placing something in the past. For instance, "He laid the cards on the table."

The past participle of "lay" is also "laid." When forming perfect tenses, such as the present perfect or past perfect, the past participle is combined with auxiliary verbs. An example sentence is "They have laid the foundation for the building."

"Lay" is a transitive verb, which means it requires a direct object to complete its meaning. For example, "She lays the book on the table." The book is the direct object of the verb "lay."

It's important to note the difference between "lay" and "lie." "Lay" is used when someone puts or places something somewhere, as in "She lays the book on the table." On the other hand, "lie" is used when someone reclines or rests in a horizontal position, as in "He lies down on the bed."

The verb "lay" is used in various idiomatic expressions, such as "lay the groundwork" (to prepare for something), "lay off" (to dismiss employees from a job), and "lay down the law" (to state something authoritatively).

Understanding the irregular conjugation of "lay" is important for accurately describing actions related to putting or placing objects in a horizontal position.