Lemmatizer:难道它不应该对一个单词的所有变形进行lemmatize吗?

I'm using the NLTK WordNet Lemmatizer for a Part-of-Speech tagging project by first modifying each word in the training corpus to its stem (in place modification), and then training only on the new corpus. However, I found that the lemmatizer is not functioning as I expected it to.I'm using the NLTK WordNet Lemmatizer for a Par