鲸生活在海洋中,用肺呼吸而且是胎生哺乳的,所以它应该属于 ( )
A:鱼类
B:两栖类
C:鸟类
D:哺乳类
给下列图片选择合适的句子或对话。
A.It's cold.
B.It's 11:00.
C. Put on a cap
D. Is it cold? -No.it isn't.It is hot
E. Take off your shoes.
针对以下四幅图,下列说法不正确的是
分解因式:(1)ax﹣ay;(2)x2﹣y4; (3)﹣x2+4xy﹣4y2.