positive series的用法和樣例：
例句
- The process of replacing polynomials by formal power series is an example of a general device known as completion.
用形式冪級數來(lái)代替多項式的過(guò)程是被稱(chēng)之為完備化的這種一般手段的一個(gè)例子。 - To terminate a computational process in accordance with some rule, e.g., to end the evaluation of a power series at a specified term.
根據某種規則終止一個(gè)計算過(guò)程，例如，對冪級數估值時(shí)，取到指定項就停止運算。
