Qhob thaiv machine, kuj tau paub tias yog pob zeb ua cov cav tov, yog cov khoom tseem ceeb hauv kev tsim kho kev tsim kho. Lawv tau tsim los tsim cov pob zeb ua kom zoo thiab tsis tu ncua. Cov cav tov no tau hloov zuj zus sijhawm, kev ua haujlwm siab T