在句子'这杯咖啡尝起来很苦'中，'尝起来'作为系词连接主语和形容词。

In the sentence 'This coffee ___tastes bitter', '___tastes' serves as a copula linking the subject to the adjective.

在句子'The sky is blue'中，'is'作为系词连接主语和表语。

In the sentence 'The sky ___is blue', '___is' functions as a ___copula linking the subject to the predicate.

这个统计模型使用高斯连接函数来模拟变量之间的依赖关系。

The statistical model uses a Gaussian ___copula to simulate dependencies between variables.