18. According to the passage, ______. 　　 A. human brains need oxygen and blood supply now and then 　　 B. touches from doctors and nurses have nothing to do with treatment 　　 C. new-born baby monkeys should stay away from their mothers 　　 D. not all the people like being touched

17. Which of the following is NOT true? 　　 A. Everyone knows that body contact can make people happier. 　　 B. People may work harder because of body contact. 　　 C. Your fingertips can do something wonderful. 　　 D. People may not understand the importance of touching.

16. How long will the thin brown skin that covers the seed crack open? 　　 A. 1 or 2 weeks.　 　　　 B. 2 or 3 weeks.　　 　　 C. 3 or 4 weeks.　 　　　 D. a few days.

　　　　　　　　　　　　　　　　　　 E

　　 You might not know it, but there is something wonderful at your fingertips. You can make people happier, healthier and more hard-working just by touching their arms or holding their hands.

　　 Doctors say that body contact(接触) is a kind of medicine that can work wonders. When people are touched, the quantity of hemoglobin (血红蛋白) - a type of matter that produces the red color in blood increases greatly. This results in more oxygen (氧气) reaching every part of the body and the whole body benefits. In experiments, bottle-fed baby monkeys were separated from their mothers for the first ten days of life. They became sad and negative. Studies showed the monkeys were more probable to become ill than other babies that were allowed to stay with their mothers.

　　 Human babies react (反应) in much the same way. Some years ago, a scientist noticed that some well-fed babies in a clean nursery (托儿所) became weak. Yet babies in another nursery were growing healthily, even though they ate less well and were not kept as clean. The reason, he concluded, was that they often had touches from nurses.

　　 Experiments show that most people like being touched. And nearly all doctors believe touch helps to reduce patients' fear of treatment. Of course there is time when a touch is not welcome. But even if we don’t like being touched, a smile can make us feel better. Smiling increases blood flow and starts the production of “happy brain” chemicals.

　　 So let’s have a big smile and don’t forget to keep in touch.

15. The word “evaporates” in the fourth paragraph means _______. 　　 A. turns into ice because of cold weather　　　　　　 　　 B. becomes very hot by the sun heat　　　 　　 C. turns into other things because of chemical change　 　　 D. becomes vapor and disappear

14. Which of the following statements is NOT true according to the passage? 　　 A. The two points of the seed are of the same shape. 　　 B. The soil in the flowerpot should neither too dry nor too wet. 　　 C. We’d better use ripe avocados to make some guacamole. 　　 D. The most popular way to use avocados is in guacamole.

13. The main idea of the first paragraph is to ______. 　　 A. tell us how to grow an avocado plant 　　 B. give us a brief introduction to avocados 　　 C. tell us the shape and color of avocados 　　 D. tell us that avocado is a fruit

5. Find a sunny spot for the plant. Water it every few days to keep the soil moist (潮湿的). Watch it during the next few months. Your avocado plant will grow a tall, straight stem (茎) and large oval leaves.

4. When the roots are about three inches long, fill a flowerpot with soil and plant the seed. Make sure that the seed is completely covered by soil and that the young leaves are above the soil.

3. After that, you will have to wait for three or four weeks. During that time, be sure to add just enough water to replace the water that evaporates into the air. The bottom of the seed should always be just below the water’s surface. The thin brown skin that covers the seed will crack(破裂) open. Roots will start growing out of the bottom of the seed. Leaves will start growing at the top.

2. Fill the jar almost to the top with water that is just slightly warm. Rest the toothpicks on the top of the jar. The more pointed end of the seed should be in the water while the flatter end should face upward.