A.worked | B.has worked | C.is working | D.works |
A.are to be blamed | B.is to be blamed | C.are to blame | D.is to blame |
A.have uncovered | B.have been uncovering |
C.are uncovering | D.are being uncovered |
A.damaged | B.was being damaged | C.had damaged | D.had been damaged |
A.knew | B.have known | C.had known | D.know |
A.was to blame ; happening | B.be to blame ; happened |
C.be blamed ; was happened | D.was to blame; had happened |
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