英语单选 It is how the young man had learned five laanguages (that) attracted the audience's
It is how the young man had learned five laanguages (that) attracted the audience's interest.这是个强调句
如果It is how the young man had learned five laanguages （what） attracted the audience's interest.如果选了what 把it看做形式主语是否可以?
我想问的是what attracted the audience's interest is how the young man had learned five laanguages为什么不行？