Key course: Important gas flies away
本文作者： TEENS
I. Getting started · Where have you seen helium being used? · What features does it have?
II. Vocabulary in use cool v. 使冷却，使变冷 |  |
| |||||||||||||||||||||||||||||||
|
|
|
主办
|
|
中报二十一世纪（北京）传媒科技有限公司版权所有，未经书面授权，禁止转载或建立镜像。 主办单位：中国日报社 Copyright by 21st Century English Education Media All Rights Reserved 版权所有 复制必究 网站信息网络传播视听节目许可证0108263 京ICP备13028878号-12  京公网安备 11010502033664号
|
| ||||||
