Survey — is intended for surveys and votes. It can be completed only once, and only by registered users.
Training test — is used in the process of learning to consolidate the material, work on the mistakes and prepare for real testing, as well as to analyze the quality of the educational material. Such a test can be performed any number of times and without time limit. As a result user will get an assessment, see the test score for each of the tasks, the correct answers and explanations for them.
Knowledge check — is designed to test educational knowledge :) . Normal testing of educational knowledge with many flexible settings.