您要查找的是不是：
- Compulsory plus optional 合作学习策略
- Support for version and team development, with a special backup and history view of your project files, plus optional integration with StarTeam. 支持个人和团队开发,使用一个专用的文件备份和历史记录来查看工程文件,使用。
- Not required or compulsory;optional. 任意的不被要求或强制的；可选择的
- Not required or compulsory; optional. 任意的不被要求或强制的；可选择的
- It is clear to all of us that two plus two is four. 二加二等于四对我们大家都很清楚。
- The insurance cover is optional. 保险范围可以随意选择。
- I think it is compulsory to look over the house. 我认为检查这栋房子势在必行。
- Range plus one optional discrete miss. 缺省值的范围并加一个随意的离散值。
- A 4-speed automatic transmission is optional. 四段自动变速器是可自由选择的。
- He seems to have mistaken a plus for a minus. 他似乎把正号误作负号了。
- Is military service compulsory in your country? 你们国家实行义务兵役制吗？
- The bill was USD10, plus USD1 for postage. 帐款是10美元，再加上一美元邮费。
- Attendance at evening prayers is not compulsory. 参加晚祷并非硬性规定。
- Is English a compulsory subject? 英语是必修科目吗？
- His experience in social work is a plus factor. 他在社会福利工作方面的经验是一个有利因素。
- An optional academic course or subject. 选修的科目选修课程或课题
- The bill was 10, plus 1 for postage. 帐款是10英镑，再加上1英镑邮费。
- The cassette player is an optional extra in this make of car. 这种型号汽车如需盒式磁带唱机费用另计。
- Certain courses are compulsory, others are optional. 某些课程是必修的，其他是选修的。
- Every one must receive9 years of compulsory education. 每人必须接受九年的义务教育。
