He didn't approach the front door at once.

他没有立即走近前门。

《柯林斯英汉双解大词典》

Gravel crackled beneath their feet as Snape and Yaxley sped toward the front door, which swung inward at their approach, though nobody had visibly opened it.

斯内普和亚克斯利快速走向前门，碎石在他们脚下噼啪作响。门打开了，尽管他们没看到任何人来开门。

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