1. 未密封的：类约束类型必须是未密封的(unsealed)参考类(数值类和密封类都是不允许的,因为它们不允许继承). 有四个System名字空间类是禁止出现在约束子句中的,它们分别是:System::Array、System::Delegate、 System::Enum和System::ValueType.

2. 未加封的：unscrupulous 无道德的 | unsealed 未加封的 | unseamed 无缝的

3. 心皮边缘不合着的：不饱和碳氢化合物 unsaturated hydrocarbon | 心皮边缘不合着的 unsealed | 不时抽薹 unseasonable bolting

adj

1. not closed or secured with or as if with a seal

e.g. unsealed goods
the letter arrived unsealed

2. not established or confirmed

e.g. his doom is as yet unsealed

Synonym: uncertain