A:He is fine.
B:He is short.
C:He walks.
降:jiàng____ xiáng____ 难:nán____ nàn ____ 鲜:xiān ____ xiǎn ____
设P(x,y)是曲线C:x2+y2+4x+3=0上任意一点,则yx的取值范围是( )
X for ________.( )
为了探究二氧化碳的性质,某同学设计了如图所示的实验