【单选题】Prof. McDonald said, “I regret ______ that this piece of writing is not well-focused.”
【多选题】用酰氯为酰化试剂时,常加入吡啶或三乙胺等试剂,其作用是 ( )
【多选题】企业在市场上所面对的竞争者大体上可分为( )
【简答题】Java源程序名为Test.java,运行它的Java程序的命令是( )。
【简答题】Prof. McDonald said, “I ____that this piece of writing is not well-focused.” (say)
【简答题】FCX Clarity采用的燃料电池是( ),蓄电池属于( )。