That job is quite difficult. I can understand why you have _____

That job is quite difficult. I can understand why you have _____so many problems.
A、run for
B、run over
C、run off
D、run into
【正确答案】：D
【题目解析】：本题考察run组成的几个短语的区别。run into，遭遇、遇到，放在空白处最合适。