Unit21《Human Biology》(Lesson 2)ppt-北师大版高二下
Unit21《Human Biology》(Lesson 2)ppt-北师大版高二下第2页

Test your memory : Look at the following numbers for about one minute and then write down as many as you can remember .

73 49 64 83 41 27 62 29 38 93 74 97

How is your memory ? more than 9, 7-8 , 4-6 , less than 3