"As far as" e.g. "As far as I can see, there is no reason to panic." Means that in my opinion, looking at all the factors that I am aware of right now, there is no reason to panic. "As far as" e.g. "As far as that goes, I'd rather not comment." Means that on that particular topic, I do not want to make a comment. It's a "nuancy" type phrase - hard to explain exactly, but I'm trying... An equivalent would be "I don't want to talk about it," but this way is both more friendly and more final, in my opinion and experience. "As long as" e.g "As long as you are going out, can you pick up some milk?" Means "since" or "because."

I see, I've got the images of these words. Your answer is very kind to me!! You said it's a figure of speech, so I must get the hang of it by using them many times. Thank you very much!!

"I'll go out tomorrow unless it rains" is just fine. "I'll go out tomorrow as long as it doesn't rain" is also fine. BUT you can't say "I'll go out tomorrow as FAR as it doesn't rain." It's tricky to explain because it really is just a figure of speech, but I think the answer is routed in time vs distance. "As LONG as it doesn't rain" means that for all the time up until it rains, you'll be outside (basically). You would use "as FAR as" with distances. Eg. He was king over all the land, as far as the eye could see. Does that help more?

Is it right this sentence? "I'll go out tomorrow unless it rains." and can I put it in next sentence? "I'll go out tomorrow as far as(as long as)it doesn't rains." Do these each words have same meaning? or is there any different meaning between them? I understood some meaning of "as far as" by your explanation, but I wanna know if you use different these words...

Can you give a sample sentence for "unless" (and perhaps the other ones, too) to help us know in what context you are asking these? Thanks!