对英国的幼儿学校的发展作出重要贡献的是()
关于下列风力发电机组说法不正确的是() ["采用双速发电机和优化转差控制都可以实现发电机的变速调节","采用双速发电机的风力发电机组变速范围有限","采用变速恒频控制的风力发电机组有较大的变速范围","采用优化转差控制的风力发电机组和变速恒频控制的的风力发电机组变速范围相同"]
请分析房地产投资的风险与收益?
1. 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 void addTopping(String topping) { 9. System.out.println(”Cannot add Toppings”); 10. } 11. public static void main(String[] args) { 12. Pizza pizza = new PepperoniPizza(); 13. pizza.addTopping(”Mushrooms”); 14. } 15. } What is the result?() [" Compilation fails."," Cannot add Toppings"," The code runs with no output."," A NullPointerException is thrown in Line 4."]
铸造用生铁共有()个牌号。 ["2","4","6","8"]
1913年,麦克米伦姐妹在英国创立()