用英语表达“人能力不行”可以有多种方式，以下是一些常见的表达：

  1. The person is not capable.
  2. The person lacks ability.
  3. The person is not skilled enough.
  4. The person’s skills are inadequate.
  5. The person is not competent.
  6. The person is not up to the task.
  7. The person is not able to perform well.
  8. The person is not proficient.
  9. The person is not qualified.
  10. The person’s abilities are limited.

根据语境和想要传达的语气，可以选择最合适的表达方式。例如，如果想要表达轻微的批评，可以说“The person is not very skilled at…”，而如果想要表达强烈的否定，可以说“The person is completely incapable of…”。