题干
7. After 15 years in the USA, Jane finally decided to ______ American citizenship.
A： concentrate o
B：apply for
C：1ook for
D： appeal to
答案(点此获取答案解析）
B
A： concentrate o
B：apply for
C：1ook for
D： appeal to
）常用作香豆素的替代品，鉴别二氢香豆素和它的一种同分异构体（ 
）需要用到的试剂有：NaOH溶液、