英语单选题求解(1) I know you've no acquaintances here yet.But ____

英语单选题求解
(1) I know you've no acquaintances here yet.But ____ Mrs.Chambers called just now.
A.the B./ C.a D.an
为什么要选C?在人名前加a是什么用法?
(2) If you ______ change your mind,please let us know.
A.shall B.should C.will D.would
为什么要选B?
(3) Lover of towns ______ I am,I realize that I owe a debt to my early country life.
A.because B.where C.who E.as
为什么选as不选where?
(4) He has failed her so many times that she no longer places any ____ on what he promises.
A.reliance B.credit
为什么不能选B?B不是可以表达信用吗?
越详细越好.