辨别分析（辨别以下观点是否正确，简要说明理由。）

国庆期间，公民上街游行欢庆节日可以不受限制。

如果没有重力，下列说法中不正确的是（   ）

Dear Mr. Wang,

    Someone comes to the office to see you in the morning, but you and your wife are out. He comes here at 10am. Because he is very busy, he goes away half an hour later. He tells me that he is your classmate at college(大学). Now he teaches Chinese in a high school(高中) in this city and he lives near the No. 6 Middle School. He is a very tall man with short hair. He wears a pair of glasses. He tells me his telephone number is 33426685. He is often at home at 7:00 pm. So you can call him in the evening.

20世纪50年代婆罗洲的许多雅克人身患疟疾,世界卫生组织采取了一种简单、直截了当的解决方法——喷洒DDT。蚊子死了,疟疾也得到了控制。可是没多久,大范围的后遗症出现了。由于DDT同时还杀死了吃屋顶茅草的毛虫的天敌——小黄蜂,导致人们的房屋纷纷倒塌。与此同时被DDT毒死的虫子后来成为壁虎的粮食,壁虎又被猫吃掉,DDT可通过食物链不断积累,对猫有很大的杀伤力,猫的数量减少又导致老鼠大量繁殖。在由老鼠带来的大规模暴发的斑疹伤寒和森林鼠疫的危险面前,世界卫生组织只得被迫向婆罗洲空降1．4万只活猫,英国皇家空军执行了这次奇特的任务——“降猫行动”。