In terms of where different atoms are in a molecule, if you have a hydrogen atom or a fluorine atom, you can pretty much guarantee they're always going to be terminal atoms.

对于不同原子在分子中的位置，如果你有一个氢原子或者一个氟原子，那你基本可以保证,它们总是最末端的原子。

麻省理工公开课 - 化学原理课程节选

These are primarily communication systems which act to allow your other organ systems to work in concert.

正是这些基本的通讯系统,保证了体内各系统的协调工作

耶鲁公开课 - 生物医学工程探索课程节选