Question

定语从句中从句的谓语动词是否随主句的谓语动词变化

Answer 1

这个不是定语从句。
是宾语从句。
不会的。He will always remember the day when his father returned from America.
主句谓语动词是will+do 而从句时过去时态。

Answer 2

定语从句中谓语动词的单复数要根据先行词来判断。所谓先行词就是定语从句所修饰的那个名词或代词，通常位于定语从句前。

These are the books which were borrowed from Peter.这些就是从彼得那里借来的书。books是先行词，复数，因此从句中动词用were.

This is the book which was borrowed from Peter.这句话先行词是book.单数，因此从句中的动词was.

不知道这样解释你清楚了吗？

Answer 3

不会。宾语从句中存在主从一致的问题。
定语从句要根据主句从句自身发生的时间来判断时态、语态。

Answer 4

会.

She said that she loved me.