问题
单项选择题
Compared to the short-run supply curve, the long-run supply curve is:（）
A. flatter.
B. steeper sloping downward to the right.
C. steeper sloping upward to the right.
答案
参考答案：A
解析：
The long-run supply curve is more elastic and flatter than the short-run supply curve. In the long run, firms in an industry can adjust their production methods and scale.