Answer: "Began" and "begun" are both forms of the irregular verb "begin," but they are used in different tenses.
"Began" is the simple past tense form of the verb, and it is used to describe an action that started and ended in the past.
Explanation: For example:
I began my homework at 7 PM last night.
In this sentence, "began" is used to describe an action that started in the past (at 7 PM last night) and ended in the past (when the homework was completed).
"Begun" is the past participle form of the verb, and it is used in the present perfect and past perfect tenses. For example:
I have begun to study for the exam.
By the time I arrived, the meeting had already begun.
In the first sentence, "begun" is used in the present perfect tense, which indicates that the action (studying for the exam) started in the past and continues up to the present. In the second sentence, "begun" is used in the past perfect tense, which indicates that the action (the meeting) had started and ended before another past action (the speaker's arrival).