Unit 2 We haven’t found life on other planets yet .
Teaching Aims and Demands:
1. Language knowledge:
New words: planet, solar, also, none, environment, air, grow, grown, part, galaxy, billion, universe, light, beyond, alone, entrance, cost, prefer, solar system
Key structures: Present perfect tense with just, already and yet. (重点)
2.To understand passages about space travel involving present perfect tense. (难点)
3. Attitudes: We should love science and our country.
Learning strate..