Learning a language can be like climbing a mountain sometimes. At the base, all you can see is the first bit of the path, so you start out confidently. After a struggle, you get to the top of a steep climb, and suddenly the mountain looks bigger. You climb and climb again, and all you can see is more of the mountain. Is there even a top? The higher you go, the more the mountain seems to grow, as you start to understand more and more of the size and complexity of the language.
And let's face it, the English language can be pretty confusing at times. There are vast numbers of words that are synonyms, or near synonyms, or sometimes synonyms and sometimes not. So what's a student to do?