随着产量的增加，总固定成本曲线将
A.一直保持不变
B.先下降，后上升
C.一直趋于下降
D.先上升，后下降
正确答案是A
Complete the following sentence with a (compound) word derived from the one(s) given in bracket.
In order to relieve the heavy traffic in Beijing, the departments concerned have made a （ ） plan.(long, term)
