We shan't remain here.
He wont' believe me.
on the afternoon of next Monday,that is, March 5th.
Who 作主语用 Who opened the door? 谁开了门?
Whom 作宾语用 To whom did you give the book? 你把那本书给了谁?
which 与 that 都可引导定语从句, which 只可用于指代前文指代的物,that还可以指代人.
(That, which, who: In current usage that refers to persons or things, which chiefly to things and rarely to subhuman entities, who chiefly to persons and sometimes to animals.)
参考资料:Merriam-Webster's Collegiate® Dictionary