THEREFORE Therefore (adverb) (por lo tanto / por consiguiente) means: for that reason; as a result; because of that; consequently; so ; then; thus. • ‘therefore’ shows that what was said (usually in the second part of the sentence) follows logically from what was said in the first part of the sentence. - The food tasted terrible; therefore I threw it in the garbage. [The food tasted terrible. For that reason, I threw the food in the garbage.] [The food tasted terrible. As a result (of the terrible tasting food), I threw the food in the garbage.] [The food tasted terrible. Because of that, I threw the food in the garbage.] [The food tasted terrible. Consequently, I threw the food in the garbage.] [The food tasted terrible, so I threw the food in the garbage.] [The food tasted terrible. Then, I threw the food in the garbage.] [The food tasted terrible, thus I threw the food in the garbage] - I missed the last bus of the night; therefore I had to walk home. [I missed the last bus of the night; therefore I had to walk home.] [I missed the last bus of the night. For that reason, I had to walk home.] [I missed the last bus of the night. As a result, I had to walk home.] [I missed the last bus of the night. Because of that, I had to walk home.] [I missed the last bus of the night; consequently, I had to walk home.] [I missed the last bus of the night, so I had to walk home.] [I missed the last bus of the night. Then, I had to walk home.] - You are interrupting the teacher; therefore you must leave the classroom. - I do not have a million dollars; therefore I cannot lend you a million dollars. - I have gained too much weight lately; therefore I must eat less and start exercising. - I just proofread what I wrote and there were no spelling mistakes or typing erros; therefore I should get a medal, or a lollipop, or a sticker. :)

Thereby = by that means, as a result of that. Therefore = for that reason Both are close and could be used in your example but, as pointed out, they have slightly different meanings. I finished all of my school assignments, therefore, I'm going home. I stayed an did extra school assignments, thereby, I got an A.

Sorry... I forgot to respond to your two sentences: a) They bought a lottery ticket therefore they won. - Buying a ticket does not mean that you will win, but it does mean that you now have a chance to win. a) They bought a lottery ticket; therefore, they had a chance to win. a) They bought a lottery ticket; thereby giving themselves a chance to win. b) They bought a lottery ticket thereby they won. - It is true that buying a ticket gives one a chance of winning... no ticket, no chance b) They bought a lottery ticket; therby giving themselves a chance to win. ******************************************************* Famous English expression: "I think; therefore I am"

THEREFORE AND THEREBY 1 The two words are similar and they have similar synonyms. 2 They can both act as conjunctions, joining two clauses together to make one sentence. 3 In some cases they are interchangeable, but not in all cases. ****************************************************************************** THEREBY • 'thereby' (adverb) (de este modo) means: by that method/means; causing something to happen; because of this or that; for this reason or for that reason; as a result; by doing that (that = the thing previously mentioned in the sentence); by doing the thing I just mentioned. • 'thereby' is often followed by the -ing form of the verb. - He knocked over the open wine bottle, thereby spilling wine on the carpet. [He knocked over the open wine bottle, (and by doing that/and because he did that) he spilled wine on the carpet.] [He knocked over the open wine bottle. For that reason, he spilled wine on the carpet.] [He knocked over the open wine bottle, and because of that, he spilled wine on the carpet.] [He knocked over the open wine bottle, (and by doing the thing I just mentioned) he spilled wine on the carpet.] [He knocked over the open wine bottle, and cause the wine to spill on the carpet.] - He tried to lift a heavy box, thereby straining his back. - They stole things from the store, thereby forcing the store owner to call the police. - I forgot that I was filling the bathtub and it flooded the bathroom, thereby costing me a lot of money for the repairs. ****************************************************************************

Hi, 1. While the meanings are mostly the same, the use of them would depend on context and sentence structure. 2. I would not use therefore or thereby in any of the contexts for A and B. Lets modify the example slightly They withdrew from the game therefore they lost They withdrew from the game thereby loosing 3. Thereby is often used in place of "by doing/by vitrue" - Example: The man is frustrated that he signed a new contract, as by doing so, he limits himself to one employer. In this scenario we can re-write it as: The man is frustrated that he signed a new contract, thereby, limiting himself to one employer. (Note the change from "he limits himself" to present participle "limiting himself") Therefore represents consequential action by reason - Example: The exams are coming up soon, for this reason, it would be a good idea to study. In this scenario we can re-write it as: The exams are coming up soon, therefore, it would be a good idea to study. Well done on picking a question where I had to question my own native language :) I hope this helps, someone else may have a better explanation :)