Which of the following statements about variables and their scopes are true? () [" Instance variables are member variables of a class."," Instance variables are declared with the static keyword."," Local variables defined inside a method are created when the method is executed."," Local variables must be initialized before they are used."]
开车时适合听的音乐类型有() ["巴洛克音乐","心水咏叹调","爵士乐","以上都有"]
不属于专业技术人员的是() ["教师","军人","民间石雕艺人","广告设计者"]
下列理论中,()是由美国的心理学家和行为科学家斯金纳提出的。 ["公平理论","归因理论","强化理论","期望理论"]
牛顿流体当温度升高时,液体粘度下降,气体粘度()。 ["升高","降低","不变","以上皆可以"]
有箱底面积为0.15rri2的配件共计500箱,如果摆码成五层高的垛,计算占地面积。