（主题句）However, other people will argue that having a home in large cities can cause damage to people’s bodies (why?)
（理由句）This is because the air has been polluted seriously. (Why? And How?)
（支持句）Nowadays, people have heaving reliance on cares, but these vehicles will generate a large amount of car fumes, which contain chemical substances, into the air to worsen the air quality. If people live there for a long time, they are more likely to suffer from respiratory disease, such as asthma and lung cancer.