注释：constraint n. [数] 约束；局促，态度不自然；强制
词根：constrain
adj.
constrained 拘泥的；被强迫的；不舒服的
adv.
constrainedly 勉强地；强迫地；不自然地
v.
constrained 驱使；强迫；勉强（constrain的过去分词）
vt.
constrain 驱使；强迫；束缚
例句：
(1) The boy felt constraint in her presence.
那男孩在她面前感到局促不安。
(2) The subject of this constraint is customer.
这个约束的主体是客户。
(3) This very simple program declares the two decision variables: the constraint and the objective function.
这个非常简单的程序声明了两个决策变量：约束和目标函数。
(4) You can name the constraint, but you do not have to.
您可以命名约束, 但这不是必须的。
(5) There have been several attempts to deal with this kind of constraint.
已经有人做了一些处理这类约束的尝试。
(6) Well, here we have to use the constraint.
这里，我们必须使用约束条件。
(7) If the language is not supported, the constraint is ignored by the tool.
如果指定的语言不被支持, 约束将会被工具所忽略。
(8) An example of a constraint is "a customer must have exactly one legal address".
约束的一个例子是 “一个客户有且只有一个合法地址”。

occasion n. 时机，机会；场合；理由
vt. 引起，惹起
词组：
occasion segmentation时机细分；场合细分
Right Occasion合适的情境；适当时刻
occasion n场合；重大或特殊的活动
词根：occasion
adj. occasional 偶然的；临时的；特殊场合的
例句：
(1) Try to dress appropriately for each occasion.
试图为每个场合适当地打扮。
(2) What you said on the occasion was not appropriate.
在这种场合你说这样的话是不相宜的。
(3) Conversation on such an occasion is not expected to soar above polite commonplaces.
不能指望在这种场合的谈话会超越平常的客套。
(4) They go with this occasion. They go with the relationships.
它们出现在这种场合，它们与关系相随。
(5) I have no occasion to see him these days.
这些天我都没有机会见到他。
(6) On what occasion do you lie?
在什么场合您会撒谎？
(7) I wish to express my sorrow on this occasion.
我希望能在此场合表达我的哀伤.
(8) Thank you for giving me this opportunity to speak about myself in this special occasion.
非常感谢给我这次机会在这种特殊的场合谈论我自己。
(9) This campaign must be the occasion, the vehicle, of your hopes, and your dreams.
这场竞选必须成为表达你们的希望和梦想的机会与平台。