Помогите решить номер 8,9,10

Question

Помогите решить номер 8,9,10

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Answer 1

Ex 8
1) Has there ever been life on Mars?
2) We just have seen a solar eclipse.
3) I have never learnt astronomy in my life.
4) She isn't hungry - she just has eaten lunch.
5) Have you ever swum in a mountain lake?