i am glad to be at your service.句型上（主谓宾）怎么分析?还有为什么是用to be at

I am glad to be I am glad to be your penfriend I'd be glad to.but I am not very good at it.would you mind teaching me? I am really glad to be dead.求上句的中文翻译. 帮帮忙单词连句 1、to am i very glad be here 2、at my are parents ,home i am glad to be at your service.句型上（主谓宾）怎么分析?还有为什么是用to be at I am glad to your I'd be glad to. We will be glad to attend或者I am very glad to meet you!为什么加will用原型be glad to do请老师指导 l`d be glad to.bat l am not very goodl`d be glad to.bat l am not very good at it.would you mind teaching i am very glad（ ）here A to be B be C come I am very glad to see you i am very glad to help you i am glad to hear from you I am glad to (h )from you. I am glad to meet you all. mum,i am happy at school.-----------.a i am glad to hear that.b yes ,i am cA I am glad to hear that.B yes ,i am C Sure D Right I am glad------help you.A.for B.at C.to D.with