1. But we must be less willing to accept superficial, theoretical announcements of right and wrong, cause and effect.
    但是我们切不可轻易接受理论上的、肤浅的是非之说和因果之说。

2. You can get a theoretical knowledge of farming from text books.
    你可以从教科书上得到关于耕作的理论知识。

3. They aroused great interest at the time, they had important theoretical consequences, and they provided a striking demonstration of the potentialities hidden in instruments and apparatus.
    这些观察当时引起人们极大的兴趣，具有重要的理论意义，并充分显示出了仪表和仪器的潜在力量。

4. I'll tell you which choice I would make in this theoretical situation.
    我来告诉你我在这种情况下会怎么做。