have a hand in
参与
A：Are you having a hand in looking into the case?
A:你参与调查那件案子了吗?
B:Yes.
B:是的。
A:How do you feel about it?
A:怎么样?
B:It's really a hard nut to crack, The probelm is that the crime was done without leaving any trace.
B：案子很棘手，问题是犯罪分子未留下任何线索。