Happy Golden Week Ya'll.
Today our phrase to help you with your English ability is, What can I tell you?
This means that something can't be explained further. There is no explainable reason.
A. How did you get 900 on your TOEIC test and not study?
B. What can I tell you? I am just good at English.
A. So, you just took my car without telling me and then had an accident??
B. What can I tell you? I made a mistake and I'm sorry.