Is this research center ________ you visited the modern equipment last year?

Jimson found the map of great valuewhen ______ Beijing.

下列熟语中，所使用的修辞手法不同于其他三项的一项是：

Did Jack come back early last night?——Yes. It was not yet eight o’clock____ he arrived home.

_____ Bob and Bill have any CDs—Yes, they____________.