请在答题纸上按下列所给词的正确顺序组成完整的句子。（每小题2分，共10分)
76. we/ body language/use /to strangers/we/when/introduced/are.
                                                            .
77. every culture/to/greet/has/developed/a/ way/formal/strangers.
                                                             .
78. If/someone/our/right hand/busy/is/greeting/it/cannot/a/weapon/be/holding.
                                                             .
79. American/youths/each other/often/greet/with/expression/ “Give me five！”
                                                            .
80. Body/language/fascinating/for/is/everyone/to/study.
                                                            .