如果我想做英文老師，我在中學的時候應該選擇 Eng Lit 還是 Eng LangLit ?

If you want to be an English teacher when you re in high school s1-s6,, you should choose English Literature.
Literature on a particular subject of study should be chosen.
There is now a vast literature on the general subject-field.
You are trying to keep abreast of the literature in your field=Eng. Lit.
Literature is written information produced and want to sell you something or give you advice
Try pass some exams.that claims on the exam on.literature.
You would spend time getting to know diverse literatures of different epochs of your course.
Novels, plays, and poetry are referred to as literature, especially when they are considered to have artistic merit for your Lit.Exam.
Hence a course in Literature is better than a studying of language and literature.