这句英语长句如何理解、拆分?An ice storm had turned the decks into frozen sheets that sent hundreds of families sliding into the sea as the ship tilted and began to go down.

An ice storm had turned the decks into frozen sheets that("that" here used to lead an attributove clause, function as the subject) sent hundreds of families sliding into the sea as ("as" here used to lead an adverbial clause of time ) the ship tilted and began to go down.
If you understand this sentence in this way ,you can know the structure of it!

An ice storm had turned the decks into frozen sheets 是主句
that sent hundreds of families sliding into the sea 修饰主句是同位语
as the ship tilted and began to go down. 是时间从句。

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这句话的主要支架是:An ice storm had turned the decks into frozen sheets
意思是:一场冰暴已经把甲板变成了一张结冰的被单.当船翘起,开始下沉的时候,甲板上几百个家庭都掉入了海里.
"that sent hundreds of families sliding into the sea "是修饰"decks"的.至于是什么成分的句子,这个我不擅长说清..
as the ship tilted and began to go down" 是个状语从句..表示一个状态.