He promised ________ his old friend during his stay in Tianjin

19世纪早期，恩格斯从伦敦到巴黎可以使用下列哪一组交通工具（    ）

The first thing _____ I'm going to do is to send an e-mail to Peter.

根据汉语意思完成句子。
____ Doing more exercise like running helps to _____________(增强)our body.
____ All of us should _________________________(戒除) smoking.
____ I want go be a doctor _______________________ (将来)
____ Mum, don't (担心)___________________ me. I'll take good care of myself.
____ Why don't you _______             __ （躺下）？

化学与生活、生产息息相关，请运用化学知识回答下列问题．