Hi Zhuoli,

I understand what you are referring to. I've found it helpful to consult the Official SAT Study Guide (which outlines the test and every type of question as well as how to answer each question correctly). Often times, we need to break down the situation and analyze the explanations further (which can be hard to do when they are brief, as you mention). Here's an excerpt from the guide with some sample questions (there are additional notes that the SAT prep online doesn't include).

Below, the first explanation says that the correct answer is the most "contextually appropriate." This is something you will often hear because context often dictates how one should use certain words. In the example below, Choice C was being used properly and (based on the definition of the word) made the most sense to use in this situation.

Essentially, you have to understand how to use these words to determine which one is not "awkward and unconventional." In order to do this, you must study the definition of words (check out this list, and others), which is something that simply must be studied. One really good way to learn new words and learn to understand how to use them is to read a variety of things (such as novels, articles, essays, etc.). It is also wise to practice these kinds of questions in the form of practice tests to determine what you need to practice.

There isn't really a clear cut way to remember how language works in this case. Some may say that if it sounds wrong, it probably is. However, if you do not know and understand word definitions, you can't be sure what is correct -- unless you practice it deliberately. It becomes much easier once you have some sort of developed intuition, which, again, comes from practicing word definitions and uses.

I hope this was useful. If you have further questions, always feel free to let me know!