大小单双最安全的打法

简介：Thirty minutes later, Su Can stopped writing and handed in the paper. There were still six unfinished questions on the paper. He scanned the class and found that most of the students had the same complaining expression. They were all discussing how difficult and pitfalls the weekly math test was. There are as many as fleas and we can't find them all. This is what we were asked to do to find trouble.