世界各国自然条件差异巨大，经济发展水平极不平衡，根据所学世界地理知识，有“石油王国”之称的是（  ）

地球的公转产生了(     )

中国人口问题的主要矛盾是（　　）

根据短文理解，选择正确答案。

    Tea to the Chinese is like coffee to the Americans. It's something that they can't live without.

    Chinese tea has a history of more than 5,000 years. It was most popular during the Tang Dynasty. China has many kinds of tea. White, yellow, green, oolong (乌龙茶), black and dark tea are the six main kinds.

    People in different places drink tea in their own way. People in Guangdong and Fujian love to drink “Kung Fu Tea” in small tea cups. They clean the teapot (茶壶) first with boiling water to warm it up. Then they fill the teapot with tea leaves before putting in the boiling water.

    In Beijing, people love jasmine flower（茉莉花）green tea. In Tibet, butter tea (酥油茶) is a popular drink to build up energy.

    There are rules to follow when we serve tea to others. Most importantly, remember to make the cup only seven-tenths full. If the cup is too full, it makes the cup too hot for them to hold.