Things made by hand are usually more expensive than produced in factories.
A:these
B:this
C:that
D:those
对于工业废气中余氯的定量测定常用的化学分析法是( )
猜一猜。
乌龟可能有多少只?(画“√”)
鸭子可能有多少只?(画“□”)
36
15
40
68