Before revision:  These systems rely on user reports for accessing new contents, which has serious problems including the slow handling of violations, the loss of normal and experienced users' time, the low quality of some reports, and discouraging feedback to new users.
After revision:  These systems rely on user reports for accessing new contents, which has serious problems such as the slow handling of violations, the loss of normal and experienced users' time, the low quality of some reports, and discouraging feedback to new users.