You shouldn't take _____ for granted that your parents care much about you and do so much for you.

[ ]

A. it              

B. that            

C. this            

D. one

如图所示各图中，P表示气体的压强，V表示体积，T表示热力学温度，t表示摄氏温度，则正确描述一定质量理想气体等压变化规律的是（　　）

A．

B．

C．

D．