第六学级（英国中等学校的最后两年，学生年龄在 16 至 18 岁之间，准备参加高级证书考试）the two final years at school for students between the ages of 16 and 18 who are preparing to take A levels (= advanced level exams)
Sue is in the sixth form now.
休正在读中学最后两年。
n.
1.
thefinaloptionalstageofschooleducationforstudentsinEnglandandWalesaged 16 to 18 inwhichtheystudyforandtakeA-levelandA/S-levelexaminations
2.
thelaststageofschoolinEnglandandWalesforstudentsbetweentheagesof 16 and 18. Studentsinthesixthformstudyfora-levelexaminationsandastudentatthisstageiscalledasixth-former.