Space Travel
Are aliens our friends?
来自太空的外星人
Humans (人类), animals, plants and lots of other things live on Earth. There are many other planets (星球) in space. Is anyone out there?
- 对本期电子报订户、有效期内的VIP教师会员和本学期初一尊享卡用户,我们开放所有内容:
- 如果您拥有以上权限,请点这里登录;
- 订阅电子报,请点这里;
- 激活VIP教师卡,请点这里;
- 激活21英语尊享卡,请点这里。