A: 'Why did you come late yesterday?' B: 'I'm sorry. I _____.'

• had been studying
• have been studying
• had studied
• have studied

A: 'Why are you late?' B: 'I'm sorry. I _____.'

• have been studying
• had been studying
• have studied
• had studied

A: 'Are you prepared for the exam?' B: 'Yes. I _____ all the materials.'

• have studied
• have been studying
• had studied
• had been studying

A: 'Why did you look so confident before the exam yesterday?' B: 'Because I _____ all the materials.'

• had studied
• had been studying
• have studied
• have been studying

A: 'How long _____ on this machine?' B: 'Two weeks! I think today will be the last day.'

• have you been working
• had you been working
• have you worked
• had you worked

A: 'How long _____ on that office before you quit?' B: 'A month. It was the longest month of my life.'

• had you been working
• have you been working
• had you worked
• have you worked

A: 'How many projects _____? B: 'Three projects up till now.'

• have you finished
• had you finished
• have you been finishing
• had you been finishing

A: 'How many projects _____ before you moved last year? B: 'Only five. I had one project left, but I gave it to my coworker.'

• had you finished
• have you finished
• had you been finishing
• have you been finishing

Let's go. I _____ all the needed preparations.

• have made
• had made
• have been making
• had been making

I _____ in this campus for five years, but I still lack a lot of knowledge.

• have been teaching
• had been teaching
• have taught
• had taught