下列函数中,图象过定点(0,1)的是( )
A:y=2x
B:y=log2x
C:y=x12
D:y=x2
①k=0时,F(x)恰有一个零点.②k<0时,F(x)恰有2个零点.
③k>0时,F(x)恰有3个零点.④k>0时,F(x)恰有4个零点.
分类单位由大到小依次排列的正确顺序是( )
—Sorry, I'm late. Has the meeting begun?—It doesn't matter. The meeting _______ for several minutes.
下列地理现象的叙述,正确的是( )