【中文這樣說】

作為香港公民,我們有必要幫助警察打擊犯罪.

【英文對比翻譯】

Chinese Style As the citizens of Hong Kong, we are necessary to help the police in their fight against crime.

American Style As the citizens of Hong Kong, it is necessary for us to help the police in their fight against crime.

it is necessary for sb to do sth 為固定用法