用所给单词的适当形式填空

1. Mary is only four years old, but she can         (speak) English.    

2.                     (arrive not) late for class.    

3. Does Tom        (have) to            (finish) his homework by five?    

4. She practices          (play) the piano every day.    

5. There are many           (rule) in our school.

有四瓶常用溶液：①BaCl₂溶液 ②NaCl溶液 ③Na₂SO₄溶液 ④CuSO₄溶液．不用其他试剂，可通过实验方法将它们一一鉴别出来，被鉴别的先后顺序是（　　）

A．①④③②

B．①③④②

C．④①③②

D．④①②③