1. We (to bring) a lot of berries from the wood. Now we shall make jam. 2. Look! Jane (to swim)
across the lake. 3. What they (to do) at six o'clock
yesterday? 4. You ever (to see) the Pyramids? 5. I (to
go) to the Caucasus two years ago. 6. We (to go) to
school every day. 7. Nick (to do) his homework by
seven o'clock yesterday. 8. You (to help) your father
tomorrow? 9. When Nick (to come) home yester-
day, his mother (to return) and (to cook) dinner in
the kitchen. 10. When I (to go) to school yesterday,
I suddenly (to remember) that I (to forget) to take
my English exercise book. 11. Yesterday grandfather
(to tell) us how he (to work) at the factory during
the war. 12. When Mr and Mrs Smith (to arrive) home,
they (to discover) that someone (to break) into their
house. Their video recorder and television (to disap-
pear). They (not to know) what they (to do) to de-
serve this bad luck. 13. The man (to get) off the bus
without paying while the conductor (to collect) fares
upstairs.​

1. We brought a lot of berries from the wood. Now we will make jam.
Explanation: The sentence is in the past simple tense, so the verb "to bring" should be in the past simple tense as well, which is "brought". The second sentence is in the present simple tense, so the verb "to swim" should be in the present simple tense, which is "swims".

2. Look! Jane is swimming across the lake.
Explanation: The sentence is in the present continuous tense, so the verb "to swim" should be in the present continuous tense, which is "is swimming".

3. What were they doing at six o'clock yesterday?
Explanation: The sentence is in the past continuous tense, so the verb "to do" should be in the past continuous tense, which is "were doing".

4. Have you ever seen the Pyramids?
Explanation: The sentence is in the present perfect tense, so the verb "to see" should be in the present perfect tense, which is "have seen".

5. I went to the Caucasus two years ago.
Explanation: The sentence is in the past simple tense, so the verb "to go" should be in the past simple tense, which is "went".

6. We go to school every day.
Explanation: The sentence is in the present simple tense, so the verb "to go" should be in the present simple tense, which is "go".

7. Nick did his homework by seven o'clock yesterday.
Explanation: The sentence is in the past simple tense, so the verb "to do" should be in the past simple tense, which is "did".

8. Will you help your father tomorrow?
Explanation: The sentence is in the future simple tense, so the verb "to help" should be in the future simple tense, which is "will help".

9. When Nick came home yesterday, his mother had returned and was cooking dinner in the kitchen.
Explanation: The first part of the sentence is in the past simple tense, so the verb "to come" should be in the past simple tense, which is "came". The second part of the sentence is in the past perfect tense, so the verbs "to return" and "to cook" should be in the past perfect tense, which is "had returned" and "was cooking".

10. When I went to school yesterday, I suddenly remembered that I had forgotten to take my English exercise book.
Explanation: The first part of the sentence is in the past simple tense, so the verb "to go" should be in the past simple tense, which is "went". The second part of the sentence is in the past perfect tense, so the verbs "to remember" and "to forget" should be in the past perfect tense, which is "had remembered" and "had forgotten".

11. Yesterday, grandfather told us how he worked at the factory during the war.
Explanation: The first part of the sentence is in the past simple tense, so the verb "to tell" should be in the past simple tense, which is "told". The second part of the sentence is in the past simple tense, so the verb "to work" should be in the past simple tense, which is "worked".

12. When Mr. and Mrs. Smith arrived home, they discovered that someone had broken into their house. Their video recorder and television had disappeared. They didn't know what they had done to deserve this bad luck.
Explanation: The first part of the sentence is in the past simple tense, so the verbs "to arrive" and "to discover" should be in the past simple tense, which are "arrived" and "discovered". The second part of the sentence is in the past perfect tense, so the verbs "to break", "to disappear" and "to know" should be in the past perfect tense, which are "had broken", "had disappeared" and "didn't know". The third part of the sentence is in the past simple tense, so the verb "to do" should be in the past simple tense, which is "did".

13. The man got off the bus without paying while the conductor was collecting fares upstairs.
Explanation: The first part of the sentence is in the past simple tense, so the verb "to get" should be in the past simple tense, which is "got". The second part of the sentence is in the past continuous tense, so the verb "to collect" should be in the past continuous tense, which is "was collecting".