Question

-----often I try,I cannot find the course. 为什么填however,而不是al

Answer 1

However often I try,I cannot find the course 的中文意思更接近“无论我怎么试,都找不到答案”

Although often I try,I cannot find the course 的意思比较接近“尽管我经常尝试,仍找不出办法来”

这两种用法在语法上都没问题,区别是语气的轻重,（你从中文翻译就能感觉出来）.所以具体用哪个还要看上下文的承接.

如果你这是考试题目,应该是上下文情景决定的；如果只是日常对话,可以不必纠结,两者都没问题.