1. 理論上是如此。
   It is so in theory.
2. 那個理論的精髓是為人民服務。
   The pith of that theory is serving for people.
3. 這種理論與已知事實不符。
   This theory is at variance with the known facts.
4. 老教授主持了一次理論物理學家的研討會。
   The old professor had presided over a seminar for theoretical physicists.
5. 這是一種理論上的可能性，但我認為這種情況不會發(fā)生。
   It's a theoretical possibility, but I don't suppose it will happen.
6. 這本書理論性太強，我需要一本實用的。
   This book is too theoretical; I need a practical one.
7. 這樣他們就能更好地把理論運用到實踐中去。
   In this way they can better apply theory to practice.
8. 終于在一六八七年他發(fā)表了他的新理論。
   Only in 1687 did he at last publish his new theory.

理的英語翻譯：

論的英語翻譯：