A.planes fly higher than at the equator B.the eyes can reach about 4,000 meters C.planes are clear of bad weather D.planes fly more quickly than at the equator
单项选择题The dates of the three main events in life are usually remembered because ().
A.of the celebrations B.they are important C.there are special ceremonies D.societies share common characteristics
单项选择题Why do forests in many parts of the world slowly disappear()
A.New trees are not looked after properly. B.Many trees have been cut down by man. C.Man has not paid enough attention to planting trees. D.All of the abov