这种胶水中添加了增量剂以降低成本。

This glue contains an ___extender to lower the production cost.

我们需要一个网络信号扩展器来改善楼上的WiFi覆盖。

We need a WiFi ___extender to improve coverage upstairs.

'-ly'是一个常见的副词扩展词缀，可以改变形容词的词性。

The '-ly' is a common adverb ___extender that can change the part of speech of an adjective.