①若a、b、c成等差数列，则B= $\frac{\pi }{3}$ ；               ②若c=4，b=2 $\sqrt{3}$ ，B= $\frac{\pi }{6}$ ，则△ABC有两解；

③若B= $\frac{\pi }{6}$ ，b=1，ac=2 $\sqrt{3}$ ，则a+c=2+ $\sqrt{3}$ ；     ④若（2c﹣b）cosA=acosB，则A= $\frac{\pi }{6}$ ．

阅读下列短文，从每小题的三个选项中选出最佳选项。

     Hello, I'm Linda. I have a garden. There are some plants and flowers in my garden. I like smelling flowers in it. Look at this small plant. It's a gift from my grandmother. It's for Children's Day. I like it very much. It is small and short. It has two small leaves. I water it every day. The plant grows and grows. Now it is big. It has more(更多) leaves. Now it has three pink flowers. They are beautiful. I like these beautiful flowers very much.

建国初期，***指出：“现在我们能造什么?能造桌子椅子，能造茶碗茶壶，能种粮食，还能磨成面粉，还能造纸，但是，一辆汽车、一架飞机、一辆坦克、一辆拖拉机都不能造。”这说明当时我国必须（    ）

某兴趣小组先往甲、乙试管中各加入2mL 10%的CuSO₄溶液，再往甲试管中加入5mL、乙试管中滴入2滴10%的NaOH溶液，观察到甲试管中有蓝色沉淀生成，乙试管中有浅绿色沉淀生成．

小明给了小芳2个苹果，现在，小明和小芳手里的苹果一样重，那么，原来谁手里的苹果比较重？