Question

【题目】The pipes have oil or water, which is heated and sent to the storage tank until to produce electricity.

A. needed B. needing

C. to need D. having needed

Answer 1

【答案】A

【解析】

试题分析：考察时间状语从句中的省略。当状语从句的主语与主句的主语一致时，可以省略状语从句的主语和系动词be 。将省略还原该句应该是sent to the storage tank until（it is）needed to produce electricity.句意：该管道内有油或者水，直到需要发电时，其才会被加热并送入存储罐中。