Questions 19 to 21 are based on the passage you have just heard. 19. A. It tastes better. B. It is easier to grow. C. It may be sold at a higher price. D. It can better survive extreme weathers. 20. A. It is healthier than green tea. B. It can grow in drier soil. C. It will replace green tea one day. D. It is immune to various diseases. 21. A. It has been well received by many tea drinkers. B. It does not bring the promised health benefits. C. It has made tea farmers' life easier. D. It does not have a stable market.