经济增长的长期趋势在图形上表现为（）。

A.正斜率的直线

B.向右下方倾斜的直线

C.波动幅度较大的曲线

D.无法判定

--- Why do you choose to go to Meiling Middle School?

---Everyone says the teachers there are strict not only ____ their students but also ____ their work.

A．with, on

B．in , with

C．in, on

D．with, in