下面各句中，表达得体的一句是

We spent all our money because we stayed at the most expensive hotel in town.—Why didn’t you stay at __________ one

Carelessness always contributes _______ car accidents. Therefore, drivers are advised to concentrate their attention _______ driving.

They all think the problem needn’t _________. It isn’tworth _________ at all.

did you stay in Hong Kong — About 20 days.