Using English prepositions and articles correctly is difficult for me. I got used to making English sentences, and I became careless about the details. I need to study the fundamentals of English grammar again to get a sure grip on them.

The development of my English skills has slowed down recently, so I have to try to speak to people more to express what I think in English words. 

I read "The Egg" by Andy Weir, I have read this many times before, but I could understand it more deeply this time.