A:分解反应
B:化合反应
C:置换反应
D:复分解反应
— I didn't hear clearly.
用恰当的单词填空完成表格。
College students volunteer in the US
In ____
They ____books to the sick people or listen to their problems.
In old people's homes
They help to clean up or go ____.
In the ____clubs
They remember the problems of boys and girls
读黄土高原图,回答问题
若x=5-2,y=2-3,则x,y满足( )