用所给单词的适当形式填空。 l. Please keep quiet! My sister is trying _____ (study). 2. If you want to be _____ (health), you must take _____ (much) exercise. 3. They _____ (make) a soccer game next year. 4. My best friend _____ (be) a famous writer in the future. 5. Your songs sound _____ (well).