这个该怎么改，请告诉我

package zyi;

    public class xixixixixixixi {
        public static void main(String[] args) {
            int grade = 75;
            if (grade > 80) {

                System.out.println("该成绩为优");
            } else if (grade > 70) {

                System.out.println("该成绩等级为良");
            } else if (grade > 60) {

                System.out.println("该成绩的等级为中");
            } else {
                System.out.println("该成绩的等级为差");
            }
        }
    }

&&和||报错的地方 丢到括号里面去