cannot

You cannot have both together..你不能二者兼得。

If you cannot do it, I will understand..如果你不能做这件事，我可以谅解。

cannot help,不得不；禁不住

cannot but,不得不，禁不住

cannot help but,不得不

cannot be too,决不会太…；怎样…也不过分；越…越好

yet cannot,不能；然而却不能

cannot too,不至于过度；越…越好

cannot help doing,不得不做

cannot help doing something,忍不住做