用所给词的适当形式填空。 1. If I felt some pain, I'd stop _____ (exercise). 2. You should tell the children _____ (ask) their parents before they eat 'candy' they find. 3. Why would it _____ (danger) to meet an 'Internet friend' alone? 4. If I _____ (be) you, I would talk to your friend about the danger of _____ (smoke).