为什么古人说雷声大就雨点小？真的是这样百分之百准确么，我咋记得暴雨是雷声大雨点也大？

(adverb for emphatic assertion)

how?

rainstorm

variant of 那麼|那么[na4 me5]

in the end

(bound form) bull's-eye; target

accurate; exact; precise

for what reason?

(used before a verb to indicate an action in progress)

I; me; my

variant of 說|说[shuo1]

to remember

such

an instance of; a case of (murder, accident, dispute etc)

greatly; freely; fully