甲级防火门的耐火极限不低于（）。
A、0.60h
B、0.80h
C、0.90h
D、1.20h
参考答案：D
It was after he got what he had desired ______ he realized it was not so important.
A．that
B．when
C．since
D．as
实际工程设计时，空调机组型号如何确定？
