不中肯

例句：

1. 1. The presentation was unconvincing, and many people left early.
   这个演讲令人难以置信，许多人提前离开了。
2. 2.He gave a convincing speech that convinced everyone of the importance of the cause.
   他发表了一个令人信服的演讲，让每个人都相信了这一事业的重要性。
3. 3. The book is unconvincing, but it has some interesting facts.
   这本书令人难以置信，但它有一些有趣的事实。