—Peter, how old is your father this year?
—______. And we just had a Party for his ______ birthday last weekend.
A:Fortieth; forty
B:Forty; forty
C:Forty; fortieth
这个图形有____条对称轴.
水是生命之源,既普通又宝贵。下列有关水的说法正确的是( )
下列常见的水生生物中属于软体动物的是( )