D91-20170619-词伙-231

1. derived= to receive or obtain something from something else

e.g. be derived from something: products that are derived from animals

e.g. derive something from something: They derive such great enjoyment from these simple games.

2. sustain the environment, exhaust fumes(本是复数)， conventional car

e.g.  The invention of electric vehicles is part of our effort to sustain the environment because these vehicles create fewer exhaust fumes than conventional cars.

3. lavish gift, lose face

e.g. Exchanging lavish gifts is a tradition in China and many people feel they lose face when giving or receiving inexpensive gifts. 

4. find it difficult, preserve biodiversity

e.g. Unless local authorities reduce the impact of city expansion on vegetation, We will find it difficult to preserve biodiversity in the coming decades.