1.

2. 知名的；出了名的；已知的
    You use known to describe someone or something that is clearly recognized by or familiar to all people or to a particular group of people.

    e.g. ...He was a known drug dealer...
           他是个臭名昭著的毒贩子。
    e.g. He became one of the best known actors of his day...
           他成了他那个时期最著名的演员之一。

3. 以…闻名的
    If someone or something is known for a particular achievement or feature, they are familiar to many people because of that achievement or feature.

    e.g. He is better known for his film and TV work.
           他的影视作品更为出名。

4. 使人们知道（或清楚）；明确表示
    If you let it be known that something is the case, or you let something be known, you make sure that people know it or can find out about it.

    e.g. The Prime Minister has let it be known that he is against it...
           首相对此明确表示反对。
    e.g. He let his preference be known to the press.
           他向记者公开了他的偏好。