I can tell which one is her best book as I am not familiar with her books.
我不知道哪一本是她最好的书,因为我不熟悉她的书。
Touch screen may also be hard to use for people who is not familiar with computers.
对于不熟悉电脑的人来说,触摸屏可能也很难使用。
Before traveling in a city you are not familiar with, you should learn the local customs first.
在去一个不熟悉的城市旅游之前,你应该先了解当地的风俗习惯。