I was ____ tired ____ I went to sleep early.
下列关于安全用药的说法中,正确的是( )
下列事件中,必然事件是( )
△ABC中,角A,B,C所对的边分别为a,b,c,已知sinA+sinC=psinB且 ac=14b2 .若角B为锐角,则p的取值范围是( )