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问题 选择题

有a、b为两个互成角度的分运动，它们的合运动为c，则下列说法正确的是(　　)

A．若a、b的轨迹为直线，则c的轨迹必为直线

B．若c的轨迹为直线，则a、b必为匀速运动

C．若a为匀速直线运动，b为匀速直线运动，则c必为匀速直线运动

D．若a、b均为初速度为零的匀变速直线运动，则c必为匀变速直线运动

答案

CD

题目分析：当物体所受合力的方向与合初速度方向不在同一条直线上，物体做的是曲线运动，例如不在同一条直线上的匀速直线运动和匀加速直线运动的合运动一定是曲线运动，AB错；CD对；故选CD

点评：本题难度较小，当物体所受合力的方向与合初速度方向不在同一条直线上，物体做的是曲线运动

单项选择题

Part 4


Questions 26-45


·Read the following article and choose the best word for each space.
·For questions 26-45, mark one letter A, B, C or D on the Answer Sheet.

iPhone Left in Hot Car for Three Hours


The normally peaceful suburban town of Winnetka is still reeling following the news Monday (26) a local resident, whose name is being (27) by police pending a full investigation, left an iPhone unattended for more than three hours in a car (28) in the hot sun.
"Responding to calls from (29) . passersby, who observed the iPhone sitting in a vehicle in the parking (30) of the Westfield Shopping Center, police arrived on the (31) at approximately 4 p.m. and immediately intervened to save the device," said Winnetka police chief Douglas Blaine. "Security cameras have shown that the iPhone had been in the car— with the doors (32) and the windows rolled (33) —since 1 p.m. Due to the tragic and highly emotional (34) of this case, we cannot say any (35) at this time."

A. careless B. concerned C. happy D. familiar

According to official police records, two officers forcibly (36) into the car at 4:07 p.m. and found the iPhone (37) face down on the dashboard. The iPhone at first showed no (38) of life, but after a tense few seconds, officers were able to wake it and get it to (39) to a series of simple touch commands. Police said that if the iPhone were left in the extreme (40) for any longer, it could have died.
The iPhone was rushed by ambulance to a nearby Apple facility for careful (41) .Miraculously, no damage to its memory, screen, or wireless capabilities was reported.
Upper-middle-class suburbanites from all over the North Shore area have reacted to the near-tragedy with an unprecedented outpouring of (42) . Hundreds of cards and letters have come streaming in, and local talk radio shows have been flooded (43) calls demanding that the iPhone’s (44) be prosecuted. Many have come forward offering to take the iPhone into their custody, and still (45) have donated free downloads, ringtones, and MP3s to the victimized object.
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多项选择题

民俗正常的扩布要通过哪几个步骤，再置于本民族的文化传统中：（）

A.集体参与

B.价值判断

C.取舍选择

D.加工改造

E.独立保存
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