根据句意和汉语注释,写出单词的正确形式。 1. When the doctor came, the victim has already stopped _______ (呼吸). 2. _______ (立即), the enemy disappeared on the early foggy morning. 3. It's not surprising to see so many _______ (推销员) in such a big electrical shop in China. 4. As we know, air _______ (污染) might cause many serious diseases.