▲你说的观点很好证伪，只需找到情态动词（的过去式）+ 一般不定式表示过去，以及情态动词 + 不定式完成体不表示过去的例子即可。

▲情态动词过去式 + 一般不定式表示过去：

1. She could play the piano when she was only six. 她只有六岁的时候就能弹钢琴了。

2. He got so drunk that he couldn't find the front door. 他喝得酩酊大醉，连家里前门都找不到了。

3. When I was young I'd listen to the radio, waiting for my favorite song. 我小时候常常听收音机等我最爱的歌。（《昨日重现》)

4. He said he wouldn't have any cold drinks. 他说他不愿喝冷饮了。

5. He would climb the mountain regardless of danger. 他决心不顾危险爬山。

6. They dared not irritate him. 他们不敢激怒他。

7. He could be unpleasant when he was younger. 他年轻的时候有时会令人不愉快。

8. I could see someone through the window. 我能看到有人在窗外。

▲情态动词 + 不定式完成体不表示过去：

推测性用法：

1. By the end of the year I will have finished reading this book. 到年底我就读完这本书了。（所谓“将来完成时”）

2. By 2010 I will have been studying English for 10 years. 到2010年我就学了10年英语了。（所谓“将来完成进行时”）

3. He could have gone to the USA by next week. 他下个星期就能到美国了。

4. He might/may have telephoned her by tomorrow. 他可能明天就给她打电话了。

5. He ought to/ should have had that tooth out by tomorrow. 他应该明天就让人拔了那颗牙了。

非推测性用法（“虚拟语气”）：

1. You could have come today/tomorrow. 你本可以今天/明天来的。

2. She should have gone to the dentist tomorrow. 她本该明天去看牙医的。

3. If I had won the lottery, I would/should/might/could have bought a yacht next year. 如果我当时中了彩票，明年我就会/该/可能/能够买上游艇了。