请英语高手帮帮我啊~~

Question

①
Do you still remember the days_____________we spend together in Australia?
【答案】:which
【问题】：不是有词组搭配--spend on 么？为啥不用on which呐 (=@__@=)？？
②
The gardener was called to tell the way____________the poor dog had died.
【答案】:that
【问题】：我觉得where可以呐~选项里有in which，为啥不用in which呐 ~~
③
That house， the doors_____________are painted white ，is my grandpa's.
【答案】:
【问题】：答案是？？？解释下！！！

Answer 1

1.词组不是直接的spend on ，spend是及物动词，后面应该有宾语，也就是spend sth. on sth.后面的on sth.可以没有，所以这个地方spend 的宾语应该是days，从句修饰的也是days ，不需要有on.
2.从句意上讲，我感觉这个地方way是方法、方式的意思。
3.of which，把这个句子改一下结构就是：whose doors are painted white.
whose = of which～～～