根据句意及首字母的提示, 填写所缺的单词。
1. Usually, the air is f _____ in the morning.
2. —Can you please tell me the way to the TV station?
    —Yes, it's across from the big _____ _____ (百货公司).
3. It's more c _____ to take a taxi to the station than take a bus, but too expensive.
4. —What are some of the d _____ of the web?
    —You may waste your time playing games. Sometimes you may be cheated (受骗) online.
5. You can take the e _____ to the second floor and turn right. You can find it there.