It seems that El Niño ____ some disasters in the world in the past few months.
A:has caused
B:is causing
C:will cause
D:caused
按顺序写出以学的11个声母。
____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____
下列物质敞口放置于空气中,会发生变质的是( )
已知一次函数y=kx+b的图像,如图所示,当x<0时,y的取值范围是( )