A:原始大气中
B:冷却降雨过程中
C:原始海洋中
D:岩石中
不等式 7−x>1 的正整数解为:____。
①函数 f(x)=sin(2x−π3) 是奇函数;
②函数 f(x)=cos(2x−π3) 的一条对称轴方程为 x=−π3 ;
③函数 f(x)=2sin(2x+π4) , x∈0,π2 ,则f(x)的值域为 0,2 ;
④函数 f(x)=cosx+3cosx,x∈(−π2,π2) 有最小值,无最大值.
所有正确结论的序号是____.
Hello! I am Lucy. This is ____ . China is a beautiful country. Look! This is ____ . It is in ____. It is very big. It is very beautiful, too. Do you know what this is? This is ____ . It is in Beijing. Beijing is the ____ of China.
A. Beijing
B. a map of China
C. Tian'anmen Square
D. capital city
E. the Palace Museum