They promised to develop a software package by the end of this year, they might have.
A. however difficult
B. how difficult
C. whatever difficulty
D. what difficulty
网友回答
A. however difficult
B. how difficult
(答案→)C. whatever difficulty
D. what difficulty
解析：和difficult，difficulty搭配的状语从句的连词分别是however difficult, whatever difficulty, 根据they might have 可知，此处句型为sb have difficulty (in) doing something，因此排除A.B。句意为他们承诺在今年年底要开发一个软件包，无论可能会有什么样的困难。无论有什么样的困难，即whatever difficulty they have 或者no matter what difficulty they have,或者however difficult it might be, no matter how difficult it might be. 排除D项。故选择C项。
【考点定位】考察状语从句。