Раскройте скобки, используя соответствующую форму глагола 1 he (not play) in front of an audience before, so he (feel) quite nervous at first.
2 by the time i (arrive), the party (just finish)
3 it (not be) the first time he (go) to an animal sanctuary.
4 nobody (know) who (steal) the rare plants.
5 by the end of the 20th century, it (become) clear that global warming (be) a serious problem.
6 the islanders (not have) any warning about the tsunami, so it (be) a terrible shock for them.
7 i (get) there too late because the group (start) sailing very early in the morning​

1) he has not played in front of an audience before, so he feels quite nervous at first.
Explanation: In this sentence, we are talking about a past event (him playing in front of an audience for the first time) that has not occurred before the present moment. Therefore, we use the present perfect tense ("has not played") to describe this experience. We also use the present simple tense ("feels") to describe his current state of feeling nervous.

2) By the time I arrived, the party had just finished.
Explanation: In this sentence, we are talking about two past events: the time when I arrived and the time when the party finished. The party finished before my arrival, so we use the past perfect tense ("had just finished") to describe the completion of the party before a specific past moment ("I arrived").

3) It has not been the first time he has gone to an animal sanctuary.
Explanation: In this sentence, we are talking about his past experiences of going to an animal sanctuary, and his current state of it not being the first time. We use the present perfect tense ("has not been") to indicate a connection between past experiences and the present moment. We also use the present perfect tense ("has gone") to describe his past actions of going to an animal sanctuary.

4) Nobody knows who stole the rare plants.
Explanation: In this sentence, we are talking about a current situation where nobody has knowledge of the person who stole the rare plants. We use the present simple tense ("knows") to describe the current state of not having this knowledge. Since we are not referring to any specific past or future time, we do not need to use any other tense.

5) By the end of the 20th century, it had become clear that global warming was a serious problem.
Explanation: In this sentence, we are talking about a past time frame (the end of the 20th century) and a past event (the clarity about global warming being a serious problem). We use the past perfect tense ("had become") to indicate that this clarity happened before the specific time frame mentioned. We also use the past simple tense ("was") to describe the state of global warming being a serious problem at that past time.

6) The islanders did not have any warning about the tsunami, so it was a terrible shock for them.
Explanation: In this sentence, we are talking about a past event (the islanders not having any warning about the tsunami) and its consequences (it being a terrible shock for them). We use the past simple tense ("did not have") to describe the absence of warning at a specific past time. We also use the past simple tense ("was") to describe the state of it being a terrible shock at that past time.

7) I got there too late because the group had started sailing very early in the morning.
Explanation: In this sentence, we are talking about two past events: my arrival and the group starting sailing. The group started sailing before my arrival, so we use the past perfect tense ("had started") to describe the completion of their action before my specific past event ("I got there"). We also use the past simple tense ("got") to describe the completion of my action at a specific past time.

Past perfect Unit 38
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Раскройте скобки, используя соответствующую форму глагола.
(not/play) in front of an audience before,
(feel) quite nervous at first.
so ne
(arrive), the party
By the time i
(just/finish).
3
(not/be) the first time he
to an animal sanctuary.
Nobody
(know) who
(steal) the rare
plants.
5
By the end of the 20th century, it
(become) clear that global warming
(be) a serious problem.
The Islanders
(not/ have) any warning about the tsunami,
(be) a terrible shock for them.
(get) there too late because the group
(start) sailing very early in the morning.