A:How many classrooms are there?
B:How many library are there?
C:How many libraries are there?
cos(3π2﹣φ)=35,且|φ|<π2,则tanφ为( )
一架飞机作匀速直线飞行时的速度是250m/s,经过1分钟飞机飞行了____m.
沿河分布是中南半岛城市分布的主要特征之一,其中老挝首都万象就分布在( )