结合你的经验说下“协调”。

牙膏里添加的单氟磷酸钠[Na₂PO₃F]可有效预防龋齿，关于单氟磷酸钠的说法正确的是（　　）

A．它是由钠、磷、氧、氟4个原子构成

B．它是由钠、磷、氧、氟4种元素组成的混合物

C．单氟磷酸钠中钠、磷、氧、氟元素的质量比为2：1：3：1

D．单氟磷酸钠中磷元素的化合价为+5价

为美化城市，还市民一个洁净、清新的生活环境，某市采取以下措施：①对开出工地的车辆进行清洗，不允许带泥上路；②限制城市内汽车、燃油助力车行驶；③发展燃气事业，减少劣质煤的燃烧；④将化工厂、化肥厂搬离城区，并对排放尾气进行达标检测；⑤大力提倡绿化、增加居民区绿化带．以上各措施中对减少空气污染物的产生有积极作用的是（　　）

A．①②③④

B．①②⑤

C．③④⑤

D．①②③④⑤

关于甲亢手术治疗的适应证，不正确的是（）

A.高功能腺瘤

B.中度以上原发性甲亢

C.甲状腺肿大有压迫症状

D.抗甲状腺药物或放射性¹³¹I治疗无效者

E.青少年患者

Americans are often in a hurry. They rush to work, rush home, and rush through their meals. Workers and students usually have only half hour or an hour for lunch. As a result, a lot of Americans go and eat in fast food restaurants. The service is quick, and the prices are cheap.
What do fast food restaurants serve Of course, many of them have hot dogs, hamburgers, fried chicken, pizza, or ice cream. But other fast food restaurants specialize (专门从事) in different foods. Some places serve roast beef. Some serve fish and seafood. In fact, you can find popular foreign dishes in fast food restaurants, too. There are Italian restaurants with Italian sausage (香肠) and spaghetti (通心粉). And there are Chinese restaurants with Cantonese (粤式的) or Sichuan foods.

What kinds of fast food are discussed in the passage
[A] American food. [B] Foreign food.
[C] Americanized foreign food.[D] Both American and foreign food.

A lot of fast food restaurants are franchises (产品经销特许权), a very popular form of business in the United States. There are many restaurants in a franchise, and each franchise has a different owner. However, all of the restaurants are under one central management, and the name of the restaurants is the same everywhere in the United States — and in foreign countries, too. This kind of central control guarantees that, for example McDonald’s hamburgers and Kentucky Fried Chicken taste the same everywhere.
In modern American life, fast food restaurants are very important. They provide quick and inexpensive meals for American people in a hurry.

铁路货物运输的基本作业，按具体作业环节可分为（）、装车、运送、（）和交付。