营养物质在体内的放能反应中释放的能量50%以上转化为热能。()
参考答案：对
过两点A（2，3），B（2，-1）作直线AB，则AB（ ）
A．平行于x轴
B．平行于y轴
C．过原点
D．无法确定
The reason______ he gave for being absent from school was ______ he had to attend his sick mother at home.
A．which; because
B．why; because
C．不填; that
D．why; that
