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Ex 2
2 It is important to send rockets into space.
3 The Earth revolves around the Sun in other orbit, earth is a planet in the solar system.
4 The idea of human life on Mars far -fetched.
5 We have obtained a lot of knowledge about the solar system in recent years.
6 The Earth rotates around the Sun every 365 days.
7 My knowledge of space is very limited. I'd like to know more about it.
8 The Moon is a satellite of the Earth.

1. 1) space заменить на system
2) moon заменить на sun
3) planet поменять на star
4) sun поменять на space
5) star поменять на planet
6) planes поменять на rockets
7) наверно, earth заменить на space