目前為止：until now, until today, so far until now 目前：so far 現在：right now, now, at present

目前为止 means so far 目前 is the same as 现在，they mean at present or now we use 现在 most in casual situation and 目前 in formal situation

目前爲止: so far, up to now 目前 = 現在: now

to be honest, there is no difference between all of them