Question

Do you want a friend whom you could tell everything to.

He was tired but still had a series of meeting to go to.
以上这两个句子的句子成分分析，关键是两个句子之后的to，不可以省略吗？

Answer 1

都不可以省略，因为这两个句子的to后面都有宾语，省略了，宾语就多余了。
Do you want a friend 主谓宾，
whom you could tell everything to.定语从句。
He was tired主系表，but转折连词，（he）still had a series of meeting（主）谓宾to go to后置定语。

追问

那为什么不能是he still had a series of meeting to go
谢谢啦亲

追答

因为是并列句啊，but是并列连词的嘛，主语又是同一个人，所以省略了后面的he啊，这样句子更简洁。

Answer 2

Do you want a friend whom you could tell everything to？疑问句
通过回答变陈述句为：I want a friend whom I could tell everthing to.
I want a friend 我想要一个朋友

whom 是引导词，引出下面的句子，并且在下面的句子中作介词的宾语

I could tell everthing to (whom) 我可以告诉他任何事

tell sth to sb 固定的用法，不能省略to，变成 tell sth sb

He was tired 句子1：他累了

but 连词 但是，连接两个并列的句子

still 仍然 是一个副词

had a series of meeting to go to. 因为和第一个句子的主语一致，所以主语he被省略了
a series of meeting 一连串的会议 to go to 要去进行/进展/开
go to meeting go 在这里当进行讲的时候，是一个vi不及物动词 你必须加一个介词才能再接名词

go to 是一个介词词组，就当一个动词用就行了