【题目】事情已经发展到双方家长被叫来的阶段。
The incident had reached to a both their parents were to be called in.

【答案】stage /position /situation；where
【解析】stage /position /situation where 考查单词以及定语从句。根据汉语意思此处填阶段的词，可以用stage /position /situation，都可以，后面是一个定语从句，缺少状语，先行词是表示模糊地点的词，故用where。因此此题填stage /position /situation where。