形容词必须的，<美>（学科）必修的
动词需要; 要求( require的过去式和过去分词 ); 想要; 命令
1. 必需的：算法(Algorithm) 必需的(Required) 推荐(Recommended) 可选(Optional)开放软件基金会(OSF)的分布式计算环境. DCE是一个被广泛接受的解决方案,用于开发和部署安全的、企业级的分布式计算应用,提供网络安全、透明的服务分配和跨平台通信的能力,
2. 要求的：社会责任进一步细分,企业的社会责任是社会在一定时期对企业提出的经济、法律、道德、和慈善四种期望. 其中,经济责任和法律责任是社会要求的(Required),道德责任是社会期望的(Expected),慈善责任是社会愿望的(Desired).
3. 要求：所有服务软件的实现必须(MUST)接受同六词格式一样的大小写不敏感的十六进制(数字). 十六进制数字可以由空格分隔,所以服务要求(REQUIRED)忽略所有的空格. 如果表示是通过空格分开的,首位的零必须保留.
4. required：req; 有经验的
1. required
1. It was the first time since 1990 that a US president has formally blocked a business transaction or required a sale on such grounds.
2. Online business websites were required to keep transaction records for at least two years.
3. They are required by law to act in the financial interests of stockholders, and could face a suit from Glazer if they block the bid.
4. At first it required " kicking some butt " as they say in the movies.
5. required的解释
5. There's so much growth that it can no longer be harvested by hand - harvesting machines are required.
6. Yeltsin had for years been dogged by heart problems that required multiple heart bypass surgery while he was still in office.
7. By now that gentle chill that required a light jacket at Beijing West Railway Station has developed into frost and snow.
8. Analysts predicted that complex procedures required by regulators for corporate bonds issuing are the main reason to blame.
9. The trip between the two cities will take only 90 minutes, half the time required to do the trip by road.
10. Students are required to learn some of his essays by rote, sometimes including punctuations.
adj
1. required的反义词
1. required by rule
e.g. in most schools physical education is compulsory
attendance is mandatory
required reading
Synonym: compulsory mandatory
2. necessary for relief or supply
e.g. provided them with all things needful