Continue to learn c language

I have learned C language for three days so far. The most difficult thing is to remember these words. For example, sizeof is to ask for the size of whoever, typedef is to customize the type. As the saying goes, it is a nickname. The keyword static has three functions: 1 is to modify local variables, which will make the life cycle longer. 2 is to modify global variables so that they cannot be used in other source files. The modified function makes it change from the external link attribute to the internal link attribute. There are many, many more.
This is still the first time I know the C language, and the memory is a little bit unable to keep up. Oops, what can I do.