后张法预应力筋，采用钢筋时的张拉程序为( )。

A．0→初应力→1.05σ_con(持荷2min)→σ_con(锚固)

B．0→初应力→1.10σ_con(持荷2min)→σ_con(锚固)

C．0→初应力→1.15σ_con(持荷2min)→σ_con(锚固)

The population of China___ to many times what it was in 1949, and most of its population ___ farmers.

A．have grown; are

B．have grown; is

C．has grown; is

D．has grown; are