He sat at the desk, __________ a novel.
In our town, wood can ___________ a fire.
In the past five years China ________ great _________.
They talked for about an hour of things and persons _____ they remembered in the school.
Don’t be in a hurry. We are supposed ____________ this problem step by step.
_________you have a rich knowledge of Chinese history, try acting as a guide for these foreign visitors.