It is our responsibility to save natural______. A: resources B: sources C: responses D: societies

A Popularity and use of natural gas B Natural gas reserves and supply C Natural gas prices D Clean fuel of choice E Disadvantages of natural gas F Natural gas consumption Paragraph 2______

16. Dr. Spock，_____ parents ______and enjoy their children. A: said;be natural B: told; to be natural C: told; be natural

All mineral water is ‘natural’, coming straight from a natural spring.

西方科学传统包括Natural Philosophy和Natural History两种。()

A long-term ____________ between these natural sources and sinks leads to the background, or natural, level of CO₂ in the atmosphere.

The term Dutch Disease was coined in ( ) to explain a sharp decline in the Dutch economy following their discovery of ( )in 1959. A: 1966, natural petroleum reserves B: 1966, natural gas reserves C: 1977, natural petroleum reserves D: 1977, natural gas reserves

__________ is a natural process.

Natural language includes human communication language, spoken language, written language, sign language, flag language, etc., and artificial language is a natural language improved on the basis of natural language. ()

It is said that synthetic fiber (合成纤维) is not as good as natural fiber. Natural fiber is said to be __________ synthetic fiber. (superior)