______ the time Brian arrives at the airport, Tony has already been waiting there.
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Combine the following pair of sentences , using “it” for a subject clause.
外毛细胞会改变内毛细胞的敏感性。()
A. 对
B. 错
等他到机场时,飞机已经起飞了。( by the time)
在校园里,车速被限制在每小时10英里。( be limited to)