______ in the queue for half an hour, the old man suddenly realized he had left the cheque in the car.
She showed the visitors around the museum, the construction _____ had taken more than three years.
It suddenly occurred to him _____ he had left his keys in the office.
New technologies have made ______ possible to turn out new products faster and at a lower cost.
Building a new school is one thing, while keeping it running smoothly is quite_______.
China has been pushing the reform of public hospitals ______ all its citizens.