【单选题】 class Pizza { 2. java.util.ArrayList toppings; 3. public final void addTopping(String topping) { 4. toppings.add(topping); 5. } 6. } 7. public class PepperoniPizza extends Pizza { 8. public voi...
【简答题】A.They should try' to know the benefits of early rising. B.They should try hard to cultivate the habit of early rising. C.They should stick with their old habit which has its own benefits. D.They shou...