you can give classroom tests once every few weeks -- sometimes even once a week. but even informal classroom tests, however, can break up learning rather than encourage it if they are set too often. this is particularly true if they are given to the class in a nervous and formal atmosphere.so, always try to make sure that your students don't feel anxious when you give them the test.

　　don't give the impression to your students that you are making a judgment on them every time you give them a classroom test. remember that students' work and abilities will not normally change greatly from week to week. for example, a student who is near the top of the class one week will not be near the bottom of the class the following week. if there is such a change, there is something wrong with the test or with the student's conditions.