Is the third grade experimental test a random test?

The experimental test in grade three is a surprise test. In the physical and chemical experiment operation test of Grade Three, each candidate takes an experiment in two subjects, and in the biological experiment operation test of Grade Two, each candidate takes an experiment. The experimental operations of physics and chemistry students in different counties are basically taken 10 minutes before the exam. Although the experimental operation examination of physics and chemistry students is included in the total score of the senior high school entrance examination, it can be counted as on-site lottery, giving students a certain preparation time.