The pipes have oil or water inside them, which is heated and sent to the storage tank until ______ to produce electricity.
| A．needed | B．needing |
| C．to need | D．having needed |
相关知识点
推荐试卷
The pipes have oil or water inside them, which is heated and sent to the storage tank until ______ to produce electricity.
| A．needed | B．needing |
| C．to need | D．having needed |
试题篮
()
粤公网安备 44130202000953号
