请帮忙翻译成英文，不要用翻译器，谢谢。

The system is sometimes slow and sometimes normal, seriously affecting our work.
This account number cannot be used, please help resolve (the issue).
The system is suddenly back to normal, but we still cannot find out the reason.

The system is sometimes very slow, sometimes ok, and this has seriously affected our work.
Sometimes this account doesn't work, please help solve this problem.
The system is suddenly back to normal again, but we still can't find the problem.

The system is sometimes slow and sometimes normal, which greatly affects our work.
This account doesn't work, please help.
The system suddenly goes back to normal, but we still can't find out where the problem is.

The system sometimes is slow and sometimes is normal, it effect our work seriously.
This account is not available, please help solve.
The system suddenly return to normal, but we still can't find out the reason.

The system is not running in a smooth way ,and it badly affected our work.
This ID is invalid,please help us to settle it down.
The system get right itself unexpectly ,but we still couldn't find the fault.

The system can be normal or quite slow, which makes us inefficient badly.
Please help me with this account, which is not valid.
The system is restored suddenly, but we are still beyond the reasons.