"Is he tall?"
As someone who has lived in China for over a year I feel like this sentence is awkwardly worded. I know it seems like a small change but I feel like 'ta gao bu gao' (I don't have characters installed on this computer) would be more appropriate.
But duo teach us that it is often used to connect the noun and the ajective, and doesn't mean "very"
I think it is safe to say that when it is required to connect the noun and the adjective, it doesn't mean "very".
But it does mean "very" when it is not required. So, the difficulty is knowing when it is required and when not.
As a first generation Chinese American, I need to point out that Duolingo teaches the usage of 很 in a misleading way. It makes room for confusion and incorrect interpretations like Denis's; however, 很 does indeed mean "very". It's a lesson taught at a very early age by parents and Chinese School teachers.
是 (shi) is not used in this manner for adjectives as it is in English. Generally an intensifier is used instead.
The way i like to think of it is that 是 is gennerally used for things like my mom is a chef or something. AAnother example of what this sentence is talking about is 我的妈妈死了。 That means my mom is dead.
I put in "他高吗" but it was marked wrong. They said the correct answer was "他高吗".