'Too' has a core meaning- 'in addition, more'. The variations are either neutral or displeased about the fact. 'then' has several closely related meanings, either at that specific time, or the time immediately following. In this case we can see both are pointing to a specific time, the difference is the definition (like: is 'now' only this exact moment, or this gerenal time, or from this time onward?) So we can see the core there. A little farther removed is the meaning 'in that case' like 'If it's true then I'll be surprised.' You can see that it's a slight variation whcih is explained fully by 'at the time when that case is true'. Not quite the same, but close and you can see how it evolved out of the same core. 'Like', however, is another story, more interesting! 'Like', resembling, comes from old Teutonic 'galiko' of which the root 'liko-' means 'form'. Other archaic forms of the word include: gelich geljk gleich (modern german) lyke lich but 'Like' meaning 'appreciate' comes from the same root! Old Teutonic 'galliko'- form! But the word got taken off into different languages to mean a different meaning- instead of describing similairty of form, describing that form being pleasing. liekan (gothic) likon likkia (old english) lykken lykke How interesting! One root split into two different meanign variations, and then reunited in modern english which merges their spelling but preserves the distinct difference in meaning! I love questions like this :)

I would put them into A but according to the Oxford dictionary, the word 'like' is derived from Middle English, from Old English ġelīċ by shortening, influenced by Old Norse líkr. Cognate with līc meaning a “‘body" or "corpse’”. then (n) adv. 1. At that time: I was still in school then. Come at noon; I'll be ready then. 2. Next in time, space, or order; immediately afterward: watched the late movie and then went to bed. 3. In addition; moreover; besides: It costs $20, and then there's the sales tax to pay. 4. Used after but to qualify or balance a preceding statement: The star was nervous, but then who isn't on the first night of a new play. 5. In that case; accordingly: If traffic is heavy, then allow extra time. 6. As a consequence; therefore: The case, then, is closed. n. That time or moment: The bus leaves at four; until then let's walk. adj. Being so at that time: the then chairman of the board. Idiom: then again From another standpoint; on the other hand: I need a vacation. Then again, so do my co-workers. [Middle English, from Old English thenne; see to- in Indo-European roots.] I hope this helps.