A:2+x+2=3x-1
B:2-x+2=3x-1
C:2-x+2=31-x
D:2-x+2=3x-1
⑴ ____
⑵ ____
⑶ ____
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A. Canada B. UK C. China D. USA
一Why are you so tired these days?
一Well,I have work to do.
如图中“□”表示人体的一些体液和排泄物的正常pH值范围,据此判断其中酸性最强的是( )