His only ambition was ________ at his job.
His only ambition was ________ at his job.
Explanation
His only ambition was to succeed at his job.
We need to use a first form of verb after was.
Succeed is a verb which means کامیاب ہونا
His only ambition was to succeed at his job means اس کا واحد مقصد اپنے کام میں کامیاب ہونا تھا
AGM 24-12-2022