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