aspect vs. tense in semitic languages

since it came up while discussing the potential of various things
happening in the development of jûdajca, a romance language in an
environment of heavy semitic influence, i realized that i don't really
understand the whole idea of aspect, especially with respect to semitic
languages.

i've been learning/speaking modern hebrew for about 13 years already,
with a heavy "adstrate influence" of vocabulary and grammatical forms
from previous periods.  and it never seemed to cross my mind that the
time system of the language doesn't work the same as my native language,
english.  sure it's a bit more simplified, but it still always seemed
like past - present - future.  there are a few anomalies floating around
here and there, but i always thought of the time systems as fundamentally
similar.

so, can anyone explain to me this relationship of aspects vs. tenses in
semitic languages, especially hebrew?

[to:'DO rab'bO],


-Stephen (Steg)
 "I gave my life to become the person I am right now.  Was it worth it?"
~ richard bach