A.completes
B.will complete
C.are completing
D.will have completed

A.am working / will retire
B.am going to work / am retiring
C.work / am going to retire
D.have been working / retire

A.will get / has been waiting
B.got / was waiting
C.got / had been waiting
D.get / will wait

A.is used
B.it is used
C.used
D.being used

A.is invented
B.is inventing
C.invented
D.was invented

A.are destroying
B.destroyed
C.were destroying
D.were destroyed

A.to be generally known
B.is generally known
C.generally known
D.is generally knowing

A.often be considered
B.can often consider
C.can often considered
D.can often be considered

A.has always been spoken
B.has been spoken always
C.has always spoken
D.had always spoken

A.before I came home after work
B.after I had came home after work
C.while I was coming home after work
D.when I come home after work