Complete the sentence with past simple or present perfect using the correct form of the verb. He has worked hard for 3 years and he is proud because he (pass) his exam.

The sentence describes a current state of pride resulting from a past action (passing the exam). The present perfect tense is appropriate here to connect the past event to the present result. Therefore, 'has passed' is the correct form.

He has worked hard for 3 years and he is proud because he has passed his exam.