根据句子意思,用括号中所给词的正确形式填空,每空填一词。 1. Three ______ (four) of the students in our class have handed in their reports. 2. You needn't be frightened because these insects are completely ______ (harm). 3. If you add some lemonade and sugar, the dish will be much ______ (taste). 4. How ______ (active) they are donating money to help the sick student! 5. Some of the film stars had been ______ (sing) before they entered the film industry.