请好心英语大手解惑!10.It has always been the policy of our firm to encourage workers to take part in social activities.it是形式主语吧?

请好心英语大手解惑!10.It has always been the policy of our firm to encourage workers to take part in social activities.it是形式主语吧?
请好心英语大手解惑!
10.It has always been the policy of our firm to encourage workers to take part in social activities.
it是形式主语吧?

请好心英语大手解惑!10.It has always been the policy of our firm to encourage workers to take part in social activities.it是形式主语吧?
的确是形式主语.鼓励工人参加社会活动一直是我公司的政策.

it是形式主语,真正主语是to encourage workers to take part in social activities