心脏的壁由厚到薄的排序，依次是[ ]
A．左心室、右心室、心房
B．右心室、左心室、心房
C．心房、左心室、右心室
D．心房、右心室、左心室
答案：A
It is becoming more and more difficult to_______the problems of traffic in some big cities of our country.
A．deal with
B．set up
C．put away
D．break down
儿自我意识产生的基本过程是（）和个别化的双向过程。
