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Getting Smarter through Language

Using the Present Perfect Tense | Practice 2

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List of Exercises

Practice 1: conversational sentences

Practice 2: academic sentences. ← (you are here)

Practice

Based on this lesson, complete the blanks in each sentence below using the verbs in parentheses. Use formal, written English, so avoid using contractions whenever possible.

When you are finished, click “Answer.”

Note. Your answers will not be submitted. When you leave this page, they will be deleted.

1. After years of research, scientists (finally / find) the cure for this disease.

After years of research, scientists have finally found the cure for this disease.

2. Astronomers (already / identify) dozens of Earth-like exoplanets; however, they (not / confirm) the existence of life on any of them.

Astronomers have already identified dozens of Earth-like exoplanets; however, they have not confirmed the existence of life on any of them.

3. Oncologists (spend) billions of dollars on cancer research in the last few decades. They (make) many important discoveries, but they are still far from finding a cure.

Oncologists have spent billions of dollars on cancer research in the last few decades. They have made many important discoveries, but they are still far from finding a cure.

4. So far this year, California (suffer) three major forest fires, which (cause) loss of life and widespread destruction.

So far this year, California has suffered three major forest fires, which have caused loss of life and widespread destruction.

5. Anthropologists (learn) a great deal about modern society by studying indigenous groups around the world.

Anthropologists have learned a great deal about modern society by studying indigenous groups around the world.

6. Rapid technological development in the last hundred years (improve) our lives in many ways. Unfortunately, technology (also / create) new problems.

Rapid technological development in the last hundred years has improved our lives in many ways. Unfortunately, technology has also created new problems.

7. Because of our reliance on smart devices, we (lose) the ability to memorize addresses and phone numbers.

Because of our reliance on smart devices, we have lost the ability to memorize addresses and phone numbers.

8. In recent years, companies (implement) family-friendly policies in the workplace. As expected, such policies (attract) employees who benefit from, for example, childcare or flextime so they can work and still care for their young children or elderly dependents.

In recent years, companies have implemented family-friendly policies in the workplace. As expected, such policies have attracted employees who benefit from, for example, childcare or flextime so they can work and still care for their young children or elderly dependents.

9. In a recent study, a psychologist (observe) that women, not men, are the ones who pick a potential romantic mate out of a crowd.

In a recent study, a psychologist has observed that women, not men, are the ones who pick a potential romantic mate out of a crowd.

10. American author Mark Twain’s witty novels (bring) enjoyment and laughter to millions of people.

American author Mark Twain’s witty novels have brought enjoyment and laughter to millions of people.

11. Recent cognitive studies (reveal) subtle differences in the way baby boomers and millennials process digital information.

Recent cognitive studies have revealed subtle differences in the way baby boomers and millennials process digital information.

12. Physicists (never / image) dark matter directly, yet they (be able) to observe its gravitational effects on distant galaxies for a long time. In fact, trying to explain such effects is the reason they (propose) the existence of dark matter.

Physicists have never imaged dark matter directly, yet they have been able to observe its gravitational effects on distant galaxies for a long time. In fact, trying to explain such effects is the reason they have proposed the existence of dark matter.

13. Since the new administration took office, (there be) serious national security issues that the president (not yet / be able / address) .

Since the new administration took office there have been serious national security issues that the president has not yet been able to address.

14. Since the beginning of the conflict, many civilians (be able) to find safety in neighboring countries. Private citizens who own a vehicle (volunteer) to transport as many people as they can away from the dangerous areas. Nonetheless, evacuations (be) slow. To date, only a few thousand people (manage) complete the perilous journey to safety.

14. Since the beginning of the conflict, many civilians have been able to find safety in neighboring countries. Private citizens who own a vehicle have volunteered to transport as many people as they can away from the dangerous areas. Nonetheless, evacuations have been slow. To date, only a few thousand people have managed complete the perilous journey to safety.

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