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．

有一种自行车安装有激光系统，人在晚上骑车时，该系统发出的激光在路面上形成“虚拟自行车道”，如图所示．它可以提醒来往车辆，注意行车安全．下列说法正确的是（   ）

已知 $f\left(2x+1\right)$ 的最大值为2， $f\left(4x+1\right)$ 的最大值为 $a$ ，则 $a$ 的取值范围（    ）

（2015·自贡）Z市在“美丽乡村”建设中，依托旧祠堂、古书院、大会堂等场所，建设集教育、礼仪、娱乐为一体的村级文化阵地综合体—文化礼堂，让农民群众在“身有所栖”的同时“心有所寄”。从“发展先进文化”角度看，建设文化礼堂这一举措的积极意义有（   ）

①有利于弘扬和培育民族精神

②有利于加强社会主义思想道德建设

③有利于发展教育科学文化

④有利于丰富人们的精神世界，增强人们的精神力量

. It was an agreement ________ could not be changed.