world."Nowhere in the world had anyone scaled up enough to create enough materials to give to manufacturers，to experiment and test them and find out what products they can make from them.This is all about getting them to a scale and getting them as economical as we can，" he said.

　　He said a decade of research and development had worked towards reducing the cost of carbonation，but admitted there were environmental concerns with mining serpentinite.There were concerns about the environmental impact of any mining operation he said，but this process was "the only thing on a scale to deal with the CO2 problem we have".He said the material could also be used to safely store carbon and backfill mines.

　　"As much as possible we want to make this an environmental solution，" he said."It is really the end state for carbon." Dawe said he saw the biggest potential for the process in the four billion tonnes of cement(水泥) made around the world each year.

　　However environmental scientist，Tim Flannery，said there were already acceptable substitutions-fly ash and bottom ash from coal­fired power stations-to make cement."I think it's more likely we'll be mining those to make negative carbon concrete and cement，" he said.

21.What can we know from Dawe's words?

A.MCi leads the way in carbon­using technology.

B.MCi's bonded material may have a bright future.

C.Serpentinite is the key to reducing carbon emissions.

D.United efforts are needed to protect the environment.

22.Which may worry Dawe when he conducted the project?

A.The shortage of investment in the project.

B.The difficulty of winning the government's support.

C.The potential market for the carbonate by­products.

D.The possible environmental damage from the mining.

23.What is Tim Flannery's attitude towards mining serpentinite?

A.Objective. B.Supportive.

C.Disapproving. D.Indifferent.

24.What is the best title for the passage?

A.Australia's Appeal for Solutions to the CO2 Problem

B.The Efficient Way of Turning CO2 into Building Products

C.The Value of Mining Serpentinite to Make Building Products

D.An Australian Firm's Plan for Turning CO2 into "Green" Concrete

答案精析

高考高频单词与短语识记排查