Do you know how large _ __ is?

Do you know how large _ __ is? Do you know how large China's population is? How high is Qmolangma?Do you know?(合并为一句) Do you know ___ __ Do you know how large the earth is?请问这里为什么要加is? Do you know how many gold medals China __-_(win)at the 2010 Do you know how large ___ is?A.population of China B.Chinese do you know the villages name?改为同义句 do you know__ __ __ __ _ How do you know he is depressed? do you know how old she is How do you know? do you know how() how do you know