A native English speaker can take a book, let's say Joyce's "Ulysses", read it and then tell us what the book is about, produce a review, write an essay about Joyce's stylistic devices etc...
The same English speaker inside the Chinese Room can take ???? sa-n guó ya(n yì (Guanzhong's "Romance of the Three Kingdoms") and fail completely at the same task, even though he possesses the instructions to manipulate the language.
But according to the thought experiment, that English speaker in the Chinese room would not fail at the task. If given the book and the question "What is the book about?" (in Chinese), his response would be indistinguishable from a native Chinese speaker.
My only point so far is to note that if his answers in Chinese are indistinguishable from a native speaker yet we say that he does not understand Chinese, then there is no reason to believe that he understands English, either. He could be using the services of an English Room.
Your example brings up another issue with the thought experiment. The typical descriptions underplay the complexity of the situation. Imagine giving the room a Chinese equivalent of this kind of question (thanks to Dennett*):
Imagine taking a capital letter D and turning it counterclockwise 90 degrees. Now place it on top of a capital letter J. What sort of weather does this remind you of?
Are we still going to insist that the room, as a whole, has no understanding?
And then, of course, there is the "read-only problem," illustrated by this question:
What is the opposite answer to the last question you were asked?
And the "external world problem":
What was the headline in the
Guangming Daily last Tuesday?
And, finally, the killer, a question which gives the room a Chinese/English relationship:
What is the English word for 'horse'?
or a combination of the previous two:
What was the headline in the
China Daily last Tuesday?
~~ Paul
* David Moser has such a question in Chinese, which I can scan and present, if you like.