Hi Liusu,
We don't memorize words. I think forced memorization is the wrong way to approach learning a new language. Instead, we need to find ways to use what we learn: writing with new vocabulary, incorporating new words into our daily speech, etc.
When I teach, I never force my students to memorize. Instead, I encourage them to integrate the vocabulary they learn into normal conversations. Constant usage is how we're going to become fluent.
Confused and confusing are not really different words. They take the same root word confuse and change the ending to fit the situation. So once you know the word confuse you can basically understand what is being said even if you don't quite understand the nuances.
A question to all English native speakers:
People said learning a language does not require vocabulary/phrase memorization but some others do not think so I am curious if you , as a native English speaker who would like to learn Chinese/Japanese/Korean （or some other Asian languages）, would you learn words, characters or phrases as a good basis to practice the foreign language? Or you have no experience acquiring any Asian foreign language yet to state that vocabulary learning is not important to become a speaker with moderate fluency in 4 skills?
There are a few tests online where you can get an estimate of how big your vocabulary is in English (for both native and non-native speakers). The FAQs and details for this one are pretty interesting to read through and may answer some of your questions:
