________ he made up his mind to take a trip to Europe?

A．When was it that

B．to That was it when

C．That it was when

D．When it was that

关于高层建筑转换层的大体积混凝土施工，转换梁常用截面高度为（）m。

A.1.6~4

B.1.6~5

C.2~4

D.2~5