从句的标志性词可以根据从句的类型和功能来区分，具体如下：

状语从句

if

unless

as long as

although

though

even though

even if

so that

because

in case

定语从句

who

whom

whose

that

which

when

where

why

名词性从句

that

if

whether

whatever

宾语从句

that

if

whether

what

where

how long

who

whom

whose

这些标志性词或引导词在从句中起着关键作用，帮助明确从句的类型和它在句子中的位置及功能。希望这些信息对你有所帮助。