“虽然我们只有四节课,但是我们还是很忙”用英语怎么说We only have four classes，but we are so busy 可以不？必须写虽然吗？光写但是可不可以/是We have only four,还是We only have four？

although/though we have only four lessons,we are still very busy.
/ we have only four lessons,but we are still very busy.

Though we only have four classes, we're still very busy.

Though we only have four classes,we are still quite busy.
用虽然.但是或所以,
写了虽然,不能写但是或所以
We only have four classes,but we are so busy
可以不?
必须写虽然吗?光写但是可不可以/
可以,虽然和但是只能写一个