Computers with wireless Internet access also have antenna radiation, because the keyboard is also an antenna. Each key on the keyboard is covered with a vertical and horizontal grid, which itself forms an antenna, and each key is scanned by high-frequency electromagnetics at any time. It can emit a large number of electromagnetic waves. Usually, people only pay attention to blocking electromagnetic waves in the case, but they ignore the electromagnetic wave leakage of the keyboard to a large extent. Based on the above discussion, which of the following can't be inferred? ['computers with wired Internet have antenna radiation problems.', 'the case has the function of preventing the electromagnetic waves from leaking out of the case.', "people's protection against computer electromagnetic radiation exists.", 'long-term work in the electromagnetic wave environment is likely to cause human damage.']