Tenses Exercise

Fill in the blanks with an appropriate tense form.

Cell phones can be ………………….. (add / adding / added) to the list of clues that can solve a crime. Recent studies ……………………. (have proved / had proved / proved) that your cell phone ……………………. (know / knows / is knowing) a lot of things about you. It knows the names and numbers of your friends and family. It also knows your DNA. Yes, traces of your DNA ………………… (linger / lingers / is lingering) on your cell phone.

DNA is a unique genetic material that …………………… (is appearing / has appeared / appears) in every cell in your body. Like your fingerprint, your DNA is unique to you and it can help in ………………….. (identify / identifying / identified) you. DNA analysis of blood, saliva or hair ……………………. (leave / left / leaving) behind at the scene of a crime can help detectives identify criminals and their victims. Now it seems that the investigators ……………………… (is got / has got / had got) another weapon to nail the criminals. And it is your cell phone.

Answers

Cell phones can be added to the list of clues that can solve a crime. Recent studies have proved that your cell phone knows a lot of things about you. It knows the names and numbers of your friends and family. It also knows your DNA. Yes, traces of your DNA linger on your cell phone.

DNA is a unique genetic material that appears in every cell in your body. Like your fingerprint, your DNA is unique to you and it can help in identifying you. DNA analysis of blood, saliva or hair left behind at the scene of a crime can help detectives identify criminals and their victims. Now it seems that the investigators have got another weapon to nail the criminals. And it is your cell phone.