李白在长江上，写下了两首情绪不同的诗，有“平身不下泪，于此泣无穷。”也有“两岸猿声啼不住，轻舟已过万重山”。李白的情绪变化主要是因为（    ）

—         will you fly to Beijing? 

— In two days.

关于以传统农业为主体的发展阶段的叙述，正确的是（   ）

    It's important to develop the healthy habits in your daily life. The following will help you become healthier and keep perfect shape.

    Eat properly. A healthy diet is very important for everybody. Breakfast is the most important meal in a day. Doctors suggest that students' breakfast should include fruit, eggs, milk, rice or noodles, because these can offer them necessary energy, help them listen carefully in class and keep them healthy. Eat enough for lunch and little for supper. But remember that too much sugar is bad for your teeth and blood. You shouldn't have too many sweet snacks and desserts in your diet, even though such food tastes delicious.

    Keep off germs(病菌). Daily tooth cleaning reduces the amount of germs which will spread diseases. Germs in the mouth arc likely to enter the blood and cause illness, even heart disease. Even if you're not sick, always remember to cough or into your arms instead of your hands because hands can spread germs to others when you touch something else. Besides, washing hands is necessary after going to the toilet or before having a meal. And you'd better rub both hands while washing them.

    Exercise regularly. Regular exercise can improve your moods and balance. What's more, it's good for bones. There are many forms of exercise: walking or running for about 30 minutes a day playing ball games twice or three times a week, swimming or dancing often. You can choose your favorite to practise regularly. You will not only feel energetic but also think better after doing exercise.

    Stay connected. Having regular communication with friends is the key to reducing stress. And sharing happiness and sadness, exchanging information with others can also help improve memory. Having a friend or a circle of friends can help you feel good.