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 atomic bombs 2 The Berlin Wall 3 4 Slavery 5 Apartheid 6 The Pyramids of Giza 7 The identity of Jack the Ripper 8 The cause of the Mary Celeste's mysterious desertion should not have been allowed to exist in the United States could have been a giant squid. The disappearance of Amelia Earhart may have been caused by engine failure. should not have been practiced in South Africa might never have been discovered might have been built by aliens should not have been dropped on Hiroshima and Nagasaki should not have been constructed during the Cold War