确定平面上某点位置的长度值，叫该点的什么坐标？（）
A、平面垂直坐标
B、横坐标
C、纵坐标
D、平面直角坐标
参考答案：D
--- ________ Tom and his mother often watch tennis matches on TV?
--- Yes, they ________.
A．Do; are
B．Are; are
C．Does; does
D．Do; do
低温回火，回火温度应在（）℃之间。
A.700～900
B.300～200
C.150～250
