问题补充:
------- What is the price of petrol these days
-------Oh, it sharply since last month.
A. is raised
B. has risen
C. has arisen
D. is increased
答案:
A. is raised
B. has risen
C. has arisen
D. is increased
解析:本题考查时态的用法。根据since last month 可知应用现在完成时。