题型:名词解释 He lost both of his parents in the big earthquake, but ________ for him, a kind couple adopted him and took good care of him.[ ]A. suddenly B. naturallyC. obviously D. luckily 查看答案
题型:名词解释 过去国内硫磺生产用催化剂品种单一,目前国内系列化催化剂品种有Al2O3,FeSO4/Al2O3, TiO2/Al2O3,TiO2,Co-Mo/Al2O3,PSR-31是一种()催化剂。(KHD:工艺基本知识th=150) 查看答案