____ students in this school is about three thousand,and_____of them are girls. A.A number of; two thirds B.The number of; two thirds C.A number of; two third D.The
More and more people believe that technologies are great for learning. Today, such teaching tools as iPads are used in a lot of courses, including language, history and science. Many teachers are s
People all over the world eat rice. 1 people, in Asia, Africa and South America 2 it every day of their lives. Some people almost do not eat 3 except rice. Rice is a kind of 4 .
是正实数，以下不等式：①
，②
，③
，④
；恒成立的序号为