Relier Pairs Modal verbs in the pastVersion en ligne Connect these two columns and construct sentences in the passive voice using should and shouldn't to comment on historical mistakes made by mankind. par Segni 1 The cause of the Mary Celeste's mysterious desertion 2 The Berlin Wall 3 The atomic bombs 4 Slavery 5 The identity of Jack the Ripper 6 Apartheid 7 8 The Pyramids of Giza should not have been allowed to exist in the United States The disappearance of Amelia Earhart may have been caused by engine failure. might never have been discovered should not have been constructed during the Cold War should not have been dropped on Hiroshima and Nagasaki could have been a giant squid. might have been built by aliens should not have been practiced in South Africa