北京市的城市道路网系统的形式为( )。
A．方格网式
B．方格网+链式
C．环形放射式
D．方格网+环形放射式
参考答案：D
“What place is it?” “Haven’t you found out we _____ back where we ______?”
A．were, had been
B．have been, are
C．are, were
D．are, had been
在空气调节中采用焓这个参数是为了计算空气热量的变化，并入为选定0℃时干空气的焓和0℃时水的焓均为零。( )
