正弦交流电压u=220sin（314t-300），则其角频率为（）。（A）30（B）

对大、中河，河宽小于50m者，在取样断面上距岸边（）水面宽处，各设一条取样垂线，共设两条取样垂线。

A.1/5

B.1/4

C.1/2

D.1/3

使用50%的蒸馏水与50%的添加剂混合而成的冷却液可保证（）不结冰。

A.-15℃

B.-25℃

C.-35℃

D.-45℃

企业事业单位文件材料的现行作用体现在（）等方面.

A.依据作用

B.执行作用

C.推动作用

D.记实作用

材料一：

洲人送去了新世界的文明，还使新旧大陆的物产得以交换和传播……没有美洲贡献的大量金银与物质财富，没有北美的自由移民垦殖区，西方资本主义的发展将会缓慢得多……东西两半球的不同文化圈的汇合，开启了人类从传统农耕文明向现代工业文明转变过程。

——黄邦和《通向现代世界的500年》

材料二：“市场总是在扩大，需求总是在增加。工场手工业也不能再满足这种需求了。于是，蒸汽和机器就引起了工业中的革命”。

——《马克思恩格斯选集》

材料三：

材料四：

指出材料一所反映的历史事件是什么？指出图中的①、②、③、④航线哪条是哥伦布的航行路线？请列举两位（除哥伦布外）与此事件有关的历史人物？

another; like; area; those; health; there; angry; sound; look; art; more; way
Why do so many people around the world love Chinese cooking In China, cooking is an (66) , just like music, dance and painting. However, there is (67) than just one kind of Chinese food. Different areas in China have special (68) of cooking because of the differences in weather and geography.
Traditional Chinese doctors believe we need a balance of yin and yang to be (69) Maybe you should eat yang foods, (70) beef when you feel weak or tired. And you should eat yin foods like tofu while you are too stressed out or (71) The Chinese believe people who eat a balanced diet should be healthier than (72) who only eat foods that taste good.
(73) is much more to Chinese food than just taste. Behind many dishes are traditions with deep meaning. One Chinese food tradition is to eat long noodles on your birthday as a symbol of long life. (74) traditional food, yuan xiao, suggests that a family will always stay together. On the Spring Festival, people often eat fish, because yu (75) like the word meaning "more than enough".
From north to south, east to west, people are sure to find some kind of Chinese food to suit their taste and interest.