一杯是浓盐水，一杯是清水，请你利用所学的知识想办法把它们区分开来。

“平沙莽莽黄入天，英雄埋名五十年。”感动中国人物林俊德入伍52年，参加了我国全部核试验任务，先后获得30多项科技成果。在癌症晚期，他仍以超常的意志工作到生命最后一刻。林俊德的事迹告诉我们 （    ）

Red Star Restaurant
The biggest and busiest restaurant in Jinan is seeking 20 waiters who have relevant (相关的) experiences in high-grade restaurants. About ¥800—1,500 per month.
Red Star Restaurant is located at 66 on Park Street.
Our phone number is 0531-8278-4560.
3 People wanted
Need 3 people who would like to work 4 evenings per week showing films. Earn $300 per week possibly. Call 469-867-6042.
Baby-sitter wanted
For a year. 3 days a week. Some flexible (灵活的) hours required.
Knowledge: above senior middle school.
Call 0431-478-9971.

Senior 3 high school students should be given enough sleeping time, ____________ they are busy preparing for exams to enter college. 

比较地球的自转与公转

比较项目	地球自转	地球公转
方向	____	____
周期	____	____
绕转中心	____	____
产生的现象（举一个即可）	____	____