From Longman Dictionary of Contemporary Englishbe up to somebodybe up to somebodya) DECIDEused to say that someone can decide about something You can pay weekly or monthly – it’s up to you. b) used to say that someone is responsible for a particular duty It’s up to the travel companies to warn customers of any possible dangers. → up
Examples from the Corpus
be up to somebody• The effect, enhanced in buildings and enclosed spaces, can be up to 16 times more destructive than conventional high explosives.• Here, at least, the level of knowledge should be up to answering more detailed questions.• It is up to Jim and Bess Hunt to investigate the case.• The water is nearly above my waist now and soon it will be up to my neck.• It is up to the parents to be parents.• It is up to the researcher not to damage that trust but to build on it.• If anyone asked what they were up to, they planned to say they were on a fishing expedition.• It is up to us to take advantage of this opportunity and make it a new start for a healthier future. 