【单选题】芳香族氨基酸中对280nm处对光有最大吸收的是
【多选题】正则表达式(regular expression)描述了一种字符串匹配的模式(pattern),主要用来:
【单选题】I regret______ the work unfinished; I should have planned everything ahead carefully.
【单选题】---Do you regret having left your first job? ---Why should I? I ______ as much, but I enjoy more of my present job.