Although he knew little about the work done in the field of physics, he succeeded ______other experienced experts failed.
  A. which            B. that            C. what            D. where

 In some countries, ____ is called "equality" does not really mean equal rights for all people.
  A. which             B. that              C. what               D. one

 The reason why she couldn’t come to the meeting was_____ she had not been invited.
  A. because            B. which            C. that            D. why

 ____ surprised me most was ______ they had finished it so quickly.
  A. What, what         B. That, that         C. What, that         D. That, what

 Maria has to baby-sit. That’s______ she can't come with us.
   A. why               B. how                C. when             D. what

 -- I rang you at about ten, but there was no reply.
    -- Oh, that was probably ____ I was seeing the doctor.
   A. when              B. why                C. what             D. that

 _______ all the inventions have in common is _____they have succeeded.
  A. What; what         B. That; that         C. What; that         D That; what

 This old computer must have been of great use to _______ did the scientific research.
  A. those           B. when           C. whoever          D. whomever

 --- Do you know _____ Mr. Black’s address is.
   --- He may live at No. 18 or No. 19 of Bridge Street. I'm not sure of _____.
  A. what; which         B. where; which         C. where ; what         D. what; where

 --- Do you know him?
--- Yes, but I can’t remember ________I met him for the first time.
A. where           B. what            C that               D. if