It is Sunday afternoon. Mary goes to do the shopping with her mother. Her mother wants to buy some food for supper. Mary wants to buy a new skirt and some school things. They come to a shop.
   “What does your shop sell?” Mary asks, “A lot of things.” The girl in the shop says. “You can buy food, drinks, clothes in our shop and school things, too.”
   Mary and her mother go in. There are many people in the shop. Mary looks at a nice white skirt.
   “How much is the skirt?” Mary asks the girl in the shop.
   “It’s eighty yuan.”
   “That’s too dear.”
   “What about the green one? It looks nice. And it’s only thirty yuan.”
   “OK, thanks a lot.”
   “You are welcome.”
    After that, Mary buys some school things, too. Here mother buys a lot of food, like bread, cakes, meat and fish. They get home very late.

①政府部门强化市场监管，打击店大欺客现象

②消费者练就一双慧眼，自觉摈弃名牌商品

③商品经营者应自觉依法经营，保护消费者的合法权益

④消费者协会发布消费警示，禁止人们购买这些品牌

给出以下命题：
①若$\alpha$、$\beta$均为第一象限角，且$\alpha >\beta$，且$\sin \alpha >\sin \beta$；
②若函数$y=2\cos (ax-\frac{\mathrm{\pi }}{3})$的最小正周期是$4\mathrm{\pi }$，则$a=\frac{1}{2}$；
③函数$y=\frac{{\sin }^{2}x-\sin x}{\sin x-1}$是奇函数；
④函数$y=\left|\sin x-\frac{1}{2}\right|$的周期是$\mathrm{\pi }$；
⑤函数$y=\sin x+\sin \left|x\right|$的值域是0,2.
其中正确命题的个数为（  ）