Question

【题目】--- Did Cathy have problems ________ out the problems?

---Yes. I found her _________ on it for nearly half an hour.

A. work; to work B. to work; working C. working; working

Answer 1

【答案】C

【解析】句意：——凯西解决这些问题有困难吗？--——是的。我发现她做了将近半个小时。have problems(in) doing sth. 做某事有困难， find sb. doing sth.发现某人正在做或持续做某事，结合句意，答案为C。