使用放线架放线时，支架的高度一般在（）m。
A.0.9～1.0
B.1.0～1.2
C.2.0～2.5
D.1.2～1.5
参考答案：D
He _____in London for many years, but he has never regretted his final decision to move back to China.
A．lived
B．was living
C．have lived
D．had lived
常用焊接坡口形式有那几种？
