I have a pencil box. It's blue. There are lots of things in it. I have a pen. It's red and long. I like it. I have three pencils. They are short. I have a ruler. It's big. I have an eraser. It's small.
以下表示人和猿不同的是( )
溶液
双缩脲试剂
碘液
斐林试剂
甲
+
﹣
乙
++
甲、乙混合
注:“+”显色,“++”显色更深;“﹣”不显色.