please check this exercise.

please check this exercise. . Fill in the blanks using the present perfect tense. One has been done for you. have come (come) to your school to emonstrate a few things about using computers for your studies. As we . (see) recently, th computeri a very important tool in the modern world. How many of u . (learn) to use the computer recentl . b. We know that pollution (become) a threat to our survival. Before the Industrial Revolution in the 19th century, people lived more in harmony with their immedipte environment. With the spread of industrialization, the problem of pollution . "14:0... . (increase). When the Earth's population was much smaller, no one believed pollution would ever resent serious problem. With the increasing population on the planet, it . . (become) a p rent that there are limits. Pollution is one of the signs that humans . (exceed) those limits. a few friends to join us for dinner. We . see) them in awhile. I (not) . the menu simple. I (buy) the meat I will cook. I with it. Will that be all right? (be) tothe market and I ... (plan) to make some pulao to go