画一画,写一写自己喜欢的动物。
____
I like____ .
Look at____ .
It's____ (colour).
It's____ (tall/short/big…).
Its ____ is____ .
Its ____ are ____ .
给出命题:“若x2+y2=0,则x=y=0”,在它的逆命题、否命题、逆否命题中,真命题的个数是( )