Japanese verb conjugation, "-sou"?

Question:

How do you use this tense?

I see many verbs that end in this form, but it's hard for me to comprehend.

Thank you.

Answer:

like the people above said, -sou means something that is about to happen, or that looks a certain way

e.g. ame ga furu = it rains, ame ga furisou = it looks like/it's about to rain
oishii = delicious, oishisou = it looks delicious

the way to conjugate it with verbs:
1. get the stem form (the masu form, without "masu"
e.g. ame ga furu (it rains) -> ame ga furimasu -> ame ga furi
neru (sleep) -> nemasu -> ne
2. add sou (desu)
e.g. ame ga furisou (desu)
nesou (desu)

with i adjectives:
1. get rid of final i
e.g. oishii -> oishi (delicious)
samui -> samu (cold)
2. add sou (desu)
e.g. oishisou (desu)
samusou (desu)

with na adjectives (or nouns, but i can't think of an example)
1. get na adjective without na
e.g. kirei(na) -> kirei (clean)
nigiyaka(na) -> nigiyaka (lively)

2. add sou(desu)
e.g. kirei sou (desu)
nigiyaka sou (desu)

desu is the polite "to be", you don't have to add it if you're not being polite
da is the informal "to be", you don't have to add it either