计算(﹣2x2)2•(﹣3x)3的结果是( )
A:40x7
B:﹣40x7
C:﹣108x7
D:400x7
请根据上述材料及心脏结构(如图所示)回答以下问题:
My grandparents are ____ ____ the country life, and they wouldn't like to live with us.
下列解释中不正确的是( )
胎儿与母体进行物质交换的结构是( )