我生病了，所以不能上课。
That was my answer too.
“我生病了， 所以不能上课" Still marked wrong as of 2019-04-08. Reported.
2020-10-21 it's accepted. But 中国人最喜欢什么语句？
How come you have to use 我 in both clauses?
Is the 'le' required here?
I've never seen 生病 used without 了.
Would it be OK to say 不能参加课？
I also wrote it without the second 我. Is it necessary here?
