----Have you found the mobile phone _____ you lost last week?

----No, but I’ve just bought a new one.

A．what

B．whose

C．whom

D．which

碳钢管的酸洗一般采用液态磷酸，若采用盐酸或硫酸，则应添加一些合适的抑制剂，以防过酸洗。