The betaine will collapse to the alkene only when these two functions are eclipsed.只有當這兩個基團移至重迭位置時碘鹽才能裂解為烯烴.The gramophone had been eclipsed by new technology such as the compact disc.激光唱片等新技術(shù)使留聲機黯然失色。Our happiness was s...
我們在南美洲為一些大公司探測石油和礦石。We dowse oil and ore in South America for big companies.這機器每小時可以破碎多少噸礦石?How many tons of ore can this machine crush in an hour?他們從礦石中提煉出黃金.They refined gold out of the ore....