A:watch TV
B:hung out
C:stay at home
分解因式:x2-2xy+y2+x-y=____
— _______ your brother a member of the basketball team?
— No, he_______ like playing basketball.
某生态系统中四种生物所占的数量关系如图所示.假设这四种生物构成一条食物链,在一段时间内,如果甲的数量增加,则可能引起( )