能源节约的理念产生于1973年的石油危机。Energy conservation as a philosophy was born out of the 1973 oil crisis.热产生于火.Heat proceeds from fire.问题正产生于此.That is where the problems begin....
How many man - days will be needed to construct this irrigation canal?修这条渠道要多少人工?She needed to find an outlet for her many talents and interests.她的多才多艺、兴趣广泛需要找个施展的机会。Empirical results are needed in the transonic Mach reg...