Identify the main clauses and the subordinating clauses:-
a) If the manager is unable to help, try the assistant manager.
b) The mayor is the person to whom you should write the letter.
c) The man whose neck was broken has recovered completely.
d) It if unfortunate that Mr. Jones will not return.

Dear student,

a) If the manager is unable to help- subordinate clause;  try the assistant manager- main clause
b) The mayor is the person to- main clause; whom you should write the letter- subordinate clause.
c) The man has recovered completely- main clause; whose neck was broken- subordinate clause.
d) It if unfortunate- main clause;  that Mr. Jones will not return- subordinate clause.

Regards