题目内容
用balance及其短语填空
She ________ ________ ________ and rode the bicycle．
She ________ ________ ________ and fell over．
The future of the nation is/hangs ________ ________ ________．(前途未卜)
We should ________ ________ ________ of nature．
His suggestion has, ________ ________, proved useful．
