This presentation is used basically for practising present perfect plus for /since. First, I project just the photographs without the information. I ask them when these inventions appeared. Having called their attention, I project the past tenses with the exact information . We go over the inventions solving vocabulary problems and checking their comprehension, and finally I ask them to build-up new sentences using present perfect and for or since. As a follow up activity I ask them to find out about other common inventions and bring them next time to class.