【中文这样说】

作为香港公民,我们有必要帮助警察打击犯罪.

【英文对比翻译】

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 为固定用法