----- Mary looks very upset. She _______ failed to pass the exam. ----- I guess so. It's very difficult after all. A must have B could have C should have D might have
--- What is the date today?--- It's _________.
She knows a lot about China as she has been to China ________.
--- May I help you, sir?--- Yes, I bought the TV the day before yesterday, but it ______.
______ the bus until it ______..
The 70-year-old man ______ exercises in the morning.