how to improve the reading

You do not need every word to understand the meaning of what you read. In fact, too much emphasis on individual words both slows your speed and reduces your comprehension. You will be given the chance to prove this to yourself, but meanwhile, let us look at the implications.
First, any habit which slows down your silent reading to the speed at which you speak, or read aloud, is inefficient. If you point to each word as you read, or move your head, or form the word with your lips, you read poorly. Less obvious habits also hold back reading efficiency. One is "saying" each word silently by moving your tongue or throat or vocal cords; another "hearing" each word you read.
These are habits which should have been outgrown long ago. The beginning reader is learning how letters can make words, how written words are pronounced, and how sentences are put together. Your reading purpose is quite different; it is to understand meaning.
It has been estimated that up to 75 % of the words in English sentences are not really necessary for conveying the meaning. The secret of silent reading is to seek out those key words and phrases which carry the thought, and to pay less attention to words which exist only for the sake of grammatical completeness.
An efficient reader can grasp the meaning from a page at least twice as fast as he can read the page loud.
Unconsciously perhaps, he takes in whole phrase or thought unit at a time. If he "says" or "hears" word to himself, they are selected ones, said for emphasis.