Do you know Australia was, as a matter of fact,________ used to be a nation of prisoners?

A．what

B． where

C． which

D．that

进行纸绝缘聚合度测量试验时，抽提后试样在室温下让溶剂挥发。将试样浸泡在蒸馏水中（）h后，用尖镊子和刀片把润湿绝缘纸刮成薄膜，并撕裂成细微纤维状。

A.1

B.2

C.3

D.4