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