（1）hear from 意为“收到……的来信”，hear from sb.意为“收到某人的来信”，相当于receive a letter from sb. 例如：

I am looking forward to hearing from you.

我期待着收到你的来信。

（2）hear of 意为“听说”，hear of sth./sb.意为“听说过某人或某物”。例如：

Have you ever heard of Mo Yan？

你听说过莫言吗？

Let's have a try.

谢谢！