Translation:Is he tall?
I don't know how old this comment is, but the introduction tips to this lesson shed some light on this subject. Most speakers DON'T use 很 when the sentence is a question ending in 吗。 If you do use both 很 and 吗 in a sentence, (ex. 他很高吗) then the speaker is probably stressing the "very" use of 很. In a nutshell: 他高吗? = Is he tall? 他很高吗? = Is he VERY tall? (Posted May 18, 2020)