There will be many changes in our life in the future. We will____ flying cars to work. We will travel to ____ . Maybe we will ____ live in space. Students won't ____  schoolbags to go to school any more. They will learn on ____ at home. And there will be robots in our home. The robots will help us do all the housework. Life will be great at that time.

美国历史学家费正清在《ChinaWatch》一书中写道：“他们每天都亲眼目睹少年们在‘阶级斗争’的借口下，对长辈进行抢劫、报复、打骂和侮辱；他们必须出席公开批判邻居、朋友、同事和父母的大会，甚至还要积极发言……”关于费正清笔下的历史事件的说法不正确的是(        )

小明同学在学习“弹力”之后，课余时间利用刻度尺、砝码、弹簧来探究弹簧弹力与其伸长量的关系．探究活动如下：