下图为二战时期美国战争海报,依据图中英文“China is Helping Us”和“Help China”判断，海报最有可能出现在（    ）

若x₁，x₂是一元二次方程x²+10x+16=0的两个根，则代数式x₁+x₂的值是____ 

选词填空。

excited, skill, may, they, without, but, include, part

    American teenagers(青少年)enjoy doing part-time jobs．They think it's an important____of growing up．They can learn some important____by doing part-time jobs and they can also make some money in this way．
    American teenagers usually begin to do part-time jobs at the age of 14．On weekdays，they____go to work a few hours a week after school．They usually work for longer at weekends．
    In summer,American teenagers are____if they find part—time jobs at camps or swimming pools．These jobs can bring____much fun．
    Some difficult jobs____teaching， nursing and police work．____these jobs can be helpful for their future．When they grow up，the students with work experience are more likely (可能的)to be successful than those____work experience．

用英语写出下列有关活动的短语。

①艺术节 ____ ②校庆日 ____

③英语测验 ____ ④英语晚会 ____

阅读短文，回答问题：磁悬浮列车

磁悬浮列车是由无接触的电磁悬浮、导向和驱动系统组成的新型交通工具，是高新技术的产物．上海磁悬浮列车于2003年1月4日正式开始商业运营．正线全长约30km，设计最高运行时速430km/h，单向运行时间7min20s．

（1）上海磁悬浮列车的结构如图甲所示．要使列车悬浮起来，车身线圈的上端是　____ 　极．

（2）如果列车在单向运行过程中，只停靠一站，那么，停靠时间约为　____ 　s（设磁悬浮列车全程均以360km/h的速度行驶）．

（3）图乙是另一种磁悬浮列车的设计原理图，A是磁性稳定的电磁铁，安装在铁轨上，B是安装在车身上（紧靠铁轨上方）的电阻非常小的螺线管．螺线管B与电磁铁A之间相互____ （选填“排斥”或“吸引”），从而使列车悬浮在铁轨上方．