Ⅰ、1、against
2、bad
3、from
4、cause
5、whenever
6、as
Ⅱ、1、smoking
2、harmful
3、breathe
4、exercising
5、Millions
Ⅲ、1、public
2、risk
3、laws
4、somebody/someone
5、harming
Ⅳ、1、Nicotine.
2、It means stopping smoking.
3、Because they are less harmful to their health.
4、T
5、F