I'm very glad that Jack is beginning to learn Chinese just like many other foreigners abroad, although I know it may be an enjoyable challenge for him.

【翻译】杰克像许多外国人那样开始学习中文，这让我很高兴，但是，我知道这对他是一个令人愉快的挑战。

【用法说明】这里的although表示转折，意为“但是，可是，然而”。通常放在主句后，引出补充说明，使语气变弱，这时可以用but 代替。此外，though 也有该用法。例如：

Our car is old although it still runs well.  我们的车旧了，然而却很好开。

The high tax policy is certainly unpopular, although it's unlikely to meet the soaring armament expenditures.  高赋税政策肯定是不受欢迎的，但也未必能满足飞涨的军备开支。

I did not know that then, although I learned it later.  当时我不知道那件事，然而我后来知道了。

They will probably win, though no one thinks so.  他们可能会获胜，但没有人这样认为。

They're very different, though they did seem to get on well when they met.  他们大不相同, 可是见面后好像还确实相处得不错。

He'll probably say no, though it's worth asking.  他很可能会拒绝, 不过问一下有益无害。

我认为：although 和 though 的这种用法跟 but 无异，视为并列连词尚未不可。