正能量是指一中健康乐观积极向上的精神动力和情感力量。在下列校园生活中展现正能量的是（    ）

①评选“先进班集体”和“校园之星”等活动

②同学们服务社会，积极参加社会公益活动

③校运会上运动健儿努力拼搏，其他同学助威呐喊

④某校毕业生的同学给母校“留下”了满地的书本和废弃物

植物和动物生命活动的基本结构功能单位是（　　）

根据短文内容，请将单词填写在题号对应的横线上。

    Taking a taxi in a certain Eastern European country can be a shocking experience. ____ is said that some taxi drivers have metal wires stuck into the passenger seats. And ____ a button is pushed, the seat will give you ____ electric shock. These taxi drivers don't do this ____ fun. They do it to tourists ____ argue about the ridiculous(可笑的，荒谬的) fares they charge. Some drivers charge as much ____ ten times the legal fare.

    They have a secret switch which makes the meters run faster. If the tourists refuse to pay, ____ are really in for a shock.

    In one case, a German woman had no ____ (choose) but to pay $120 for a $ 20 ride from the airport. She said that she was "really taken for a ride," but what could she do? Besides the electric shock, she ____ (threaten) with physical violence. She has only one piece of advice for tourists, “Take the bus ____ stay at home.”