on the assumption that    
英[ɔn ðə əˈsʌmpʃən ðæt]    
美[ɑn ði əˈsʌmpʃən ðæt]    
adv.   假设    
[例句]Plan a was predicated on the assumption that greece could be safely quarantined.
a计划的前提假设是,欧盟可以安全地将希腊隔离开来.