单选题 Due to the unusually cool weather last month, the number of visitors to the state's major theme parks was ______ lower than forecast.
A. extremely
B. highly
C. significantly
D. well

【正确答案】 C
【答案解析】副词significantly(大大地)在此处修饰lower(较低的)的幅度。选项(A)extremely(极其)、选项(B)highly(非常)和选项(D)well(好)均不能修饰形容词比较级。