一个高中英语单选题----高手进
32、NotuntilIwasseated_____thatAirChinaprovidedwirelessnetworkserviceforitspassengersonitsBeijing-Chengduflight.
A:didIrealizeB:IdidrealizeC:IrealizeD:realizedI
此题考查知识点是什么?
最后请标准翻译,看不懂句子.