202 Present Perfect Simple And Progressive

The Present Perfect Have/Has + Past Participle

Time ? X X

1.The present perfect expresses the idea that something happened before now, at an unspeciﬁed time in the past Time ? X X

1.The present perfect expresses the idea that something happened before now, at an unspeciﬁed time in the past

1.The present perfect expresses the idea that something happened before now, at an unspeciﬁed time in the past The Raelians claim that they have cloned human beings.

1.The present perfect expresses the idea that something happened before now, at an unspeciﬁed time in the past The Raelians claim that they have cloned human beings. Has anyone succeeded in cloning animals?

1.The present perfect expresses the idea that something happened before now, at an unspeciﬁed time in the past The Raelians claim that they have cloned human beings. Has anyone succeeded in cloning animals? The egg has had its nucleus removed.

The adverbs ever, never, already,yet still, and just are frequently used with the present perfect.

The adverbs ever, never, already,yet still, and just are frequently used with the present perfect. Human beings haven’t been successfully cloned yet.

The adverbs ever, never, already,yet still, and just are frequently used with the present perfect. Human beings haven’t been successfully cloned yet. I have already seen that video on stem cell research.

The adverbs ever, never, already,yet still, and just are frequently used with the present perfect. Human beings haven’t been successfully cloned yet. I have already seen that video on stem cell research. Dr. Suzuki started writing a complaint letter to the newspaper, but he still hasn’t ﬁnished it.

The adverbs ever, never, already,yet still, and just are frequently used with the present perfect. Human beings haven’t been successfully cloned yet. I have already seen that video on stem cell research. Dr. Suzuki started writing a complaint letter to the newspaper, but he still hasn’t ﬁnished it. Alex feels bad. He has just heard some bad news.

X X X XX

2. The present perfect also expresses the repetition of an activity before now.The exact time of repetition is not important. X X X XX

2. The present perfect also expresses the repetition of an activity before now.The exact time of repetition is not important.

2. The present perfect also expresses the repetition of an activity before now.The exact time of repetition is not important. We have had four tests so far this semester

2. The present perfect also expresses the repetition of an activity before now.The exact time of repetition is not important. We have had four tests so far this semester There have been many cloning experiments done on mice.

2. The present perfect also expresses the repetition of an activity before now.The exact time of repetition is not important. We have had four tests so far this semester There have been many cloning experiments done on mice. Dr. Suzuki has spoken on the subject of cloning many times.

3.The present perfect also expresses a situation that began in the past and continues to the present. These verbs are usually stative verbs.

3.The present perfect also expresses a situation that began in the past and continues to the present. These verbs are usually stative verbs. I have been here since seven o’clock.

3.The present perfect also expresses a situation that began in the past and continues to the present. These verbs are usually stative verbs. I have been here since seven o’clock. We have been here for two weeks.

3.The present perfect also expresses a situation that began in the past and continues to the present. These verbs are usually stative verbs. I have been here since seven o’clock. We have been here for two weeks. Scientists have known this fact for a very long time.

3.The present perfect also expresses a situation that began in the past and continues to the present. These verbs are usually stative verbs. I have been here since seven o’clock. We have been here for two weeks. Scientists have known this fact for a very long time. I have liked watching science documentaries ever since I was a child.

Difference between since and for Since + a particular time (1984, 2 pm, etc.) For + a duration of time (2 weeks, half an hour, etc.)

Present perfect vs.simple past

Present perfect vs.simple past 1. Most countries (ban) ______________ by law human reproductive cloning.

Present perfect vs.simple past have banned 1. Most countries (ban) ______________ by law human reproductive cloning.

Present perfect vs. simple past

Present perfect vs. simple past 2. Dolly the sheep (be, not) ___________ the ﬁrst animal to be cloned.

Present perfect vs. simple past 2. Dolly the sheep (be, not) was not ___________ the ﬁrst animal to be cloned.

Present perfect vs.simple past

Present perfect vs.simple past 3. Japanese studies (show) ______________ that cloned mice live in poor health.

Present perfect vs.simple past 3. Japanese studies (show) have shown ______________ that cloned mice live in poor health.

The Present Perfect Progressive 1. This tense is used to indicate the duration of an activity that began in the past and continues to the present. When the tense has this meaning, it is used with time words such as, for, since, all morning, all day, all week.

The present perfect progressive

The present perfect progressive For years, scientists have been working on ways to successfully clone animals. Al Gore has been studying climate change for twenty straight years. Scientists have been debating the issue of human reproductive cloning for years.

The present perfect progressive 2. When the tense is used without any speciﬁc mention of time, it expresses a general activity in progress recently, lately.

The present perfect progressive He has been thinking about doing something to save our environment. All of the students have been studying hard for the ﬁnal. My back hurts, so I have been sleeping on the ﬂoor lately. The bed is too soft.

The present perfect progressive 3. With certain verbs (most notably live, work, teach), there is little or no difference in meaning between the two tenses when since or for is used.

present perfect progressive I have lived here since 1995. = I have been living here since 1995. He has worked at the same institution for ten years. = He has been working at the same institution for ten years.

Present perfect / progressive? Scientists (warn)____________that it would be unethical to contemplate adapting the method to help infertile couples have their own biological children.

present perfect or progressive? Scientists have warned that it would be unethical to contemplate adapting the method to help infertile couples have their own biological children.

present perfect or progressive? Scientists (conduct) ____________ experiments for years in an attempt to create a complex organism that is a clone of another organism.

present perfect or progressive? Scientists have been conducting experiments for years in an attempt to create a complex organism that is a clone of another organism.

present perfect or progressive? Scientists (clone) ________ animals for many years.

Scientists have been cloning animals for many years.

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202 Present Perfect Simple And Progressive

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