で 1) at, in わたしはとうきょうではたらく (私は東京で働く) = I work in Tokyo. 2) by わたしはくるまでつうきんする (私は車で通勤する) = I commute by car. 3) because of, due to しあいはあめでちゅうしになった (試合は雨で中止になった) = The game was called off due to rain. 4) by, in (time) こうじはあと2~3にちでおわる (工事はあと2~3日で終わる) = The construction will be over in the next few days. 5) on わたしはかのじょとでんわではなした (私は彼女と電話で話した) = I talked to her on the phone. て 1) and わたしはべんきょうをしてつかれた (私は勉強をして疲れた) = I studied and got tired. 2) (て at the end of a sentence -> ask, request, order) でんわして (電話して) = Call me, むかえにきて (迎えに来て) = Come pick me up. They can be used for many meanings, but I hope this helped... =)

Megumi-san is really on the right track, so let me just add something :) The difference of TE/DE is a grammar matter rather than the meaning. Te-form of verb takes -TE or -DE depending on the verb. For example, "kaku(write)" becomes "kaiTE," whereas "yomu(read)" becomes "'yonDE." Adjectives also take -TE/-DE for some expressions. I-adjectives such as "ookii" become "ookikuTE," whereas na-adjectives such as "genkina" become "genkiDE" After a noun, it's always -DE. It might be a conjugated copula "da/desu," or it might be a particle DE. It depends on the sentence.

Could we have some examples? There are lots of different uses for both.... "Te" could be the "te" form of verbs (ex. tabete) "De" could also be the te form of verbs (I can't come up with any right now.... ^-^*) "De" is also a particle meaning "with, by means of"; or it marks the place of action; cause, etc. It does lots of things! http://japanese.about.com/library/weekly/aa091601a.htm Please feel free to send me a message if you have any questions! ~Megumi