我知道數學課不受歡迎。
I am sensible of the fact that mathematics is not a popular subject.
令人驚訝的是，數學課被選為他們最喜歡的科目。
Surprisingly, mathematics was voted their favourite subject.
他講數學課。
He gives lessons in mathematics.
How many subjects are you taking this year?
你今年修多少門課？
How many times do I have to tell you not to do that?
我得跟你說多少回不要做那種事？