写作提纲：有关雅思写作“公共场所(超市)安装监视器利弊”
1. 安装监视器的优点： 利用监视器可以帮助警察catch criminals, thus reducing crime. a camera is more effective than security guards. 警察和保安不可能全天24小时工作，而camera will not feel tired.而且它更objective, sometimes our eyes might deceive us, while a machine can exactly record what...