German phrase
Ich kann ~ nicht helfen.
Meaning
I can't help ___
When to use it
You cannot help. Use it to politely refuse a request for help.
Example dialogue
Ich kann dir bei den Matheaufgaben nicht helfen.
I can't help you with the math problems.
Schade, hast du einen Tipp, wer helfen kann?
That's too bad. Do you have a suggestion for who can help?