In English, there are 2 ways to join a sentence: Subordination or Coordination.
Subordination is used for emphasising one part:
- Time: when, whenever, after, as, before, once, since, till, until, now, that, while, as long as, as soon as.
- Concession: though, although, even though, if, while.
- Contingency: if, once
- Condition: if, in case, as long as, unless provided that.
- Reason: because, since, as long as.
- Result: so, so that.
- Comparison: as, just as, as if.
- Contrast: while, whereas.
- Coordination is used for equal emphasis: and, or, but, yet, nor, for.