Unit One Scientific Research (Ⅰ) ·················· 001 Unit Two Scientific Research (Ⅱ)·················`· 025 Unit Three Safety (Ⅰ)························ 049 Unit Four Safety (Ⅱ) ························ 073 Unit Five Gap (Ⅰ) ····················`····· 097 Unit Six Gap (Ⅱ)·······················`··· 123 Unit Seven Gender (Ⅰ)························ 147 Unit Eight Gender (Ⅱ) ·····················`·· 171 Unit Nine Entertainment (Ⅰ)····················· 197 Unit Ten Entertainment (Ⅱ) ·················``··· 221 Unit Eleven Education (Ⅰ)······················ 245 Unit Twelve Education (Ⅱ) ·················`···· 269