It is argued that "A noha B da" is founded easily when the focus B and predicate verb in A has close semantic relations. Moreover, prepositions in Japanese corresponding do not exist in the focus B in such sentences. 当被焦点化的成分B与原谓语动词的语义关系紧密时,该句式就容易成立,而且在焦点化位置一般不出现相应的格助词;