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