先行詞是the way,place,time,reason關系副、代詞何時可省?
為什么這句要加where:
We've all used thermometers to measure temperature but sometimes we need to measure temperature in places WHERE you can't put a thermometer.
語法說,先行詞是the way,表示方式,可用that（可?。┗騣n which來引導一個定語從句.如果先行詞是時 間或原因,也可用that（可?。┗騱hen或why來引導定語從句.如：
（1）This was the reason that/why he was late yesterday.
（2）This is the last time that I shall give you a lesson.
這句是道改錯題,還要加上where 是什么原因?
沒表達清楚，我的意思是
that代替關系副詞，那么我這道改錯題為何還要加where?
有關that用法說明如下：that可以用于表示時間、地點、方式、理由的名詞后取代when,where,why和"介詞+ which"引導的定語從句，在口語中that常被省略，例如：
He is unlikely to find the place (that / where / in which) he lived forty years ago.他不大可能找到他四十年前居住過的地方。