1. Do you know? Who is the tallest student?

Question

2. Do you know who the tallest person is?
3. Do you know who is the tallest person?
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In #1, there are two sentences. When they are combined, which one is correct, #2 or #3?

Answer 1

#2 is the correct indirect question form of #1. Indirect questions need to have the word order changed, mostly in the placement of the verb.