caused the accident is still a complete mystery.
The reason _______ he was late was _______ he missed the bus.
The tiger, once a ____ animal to humans, is now ____of disappearing on the earth.
That hotel is always full because it offers a friendly____and personal service.
---Did you watch the programme I’m a singer on Friday night? It was wonderful.---I wish I had, but I _______for the mid-term examination.
It remains a question_______we can finish the project in such a short time.