Semantic Features are a source for expectancies.
You probably had no problem filling in the words “the” and “big” and “frightened; although you had to find them in your a memory bank of words from a list of more than 100,000 words.
But you knew that in English, a determiner comes typically first before the noun, and that may be followed by an adjective; and that a noun or adjective will follow the copula. We may not know we know it, but we do!
This unconscious grammatical knowledge (linguistic competence) narrows sharply the range of words we need to search among in our lexicon.
Add to this our knowledge of the semantic features of words, and our familiarity with the cultural scripts in which they occur, and we know much of the time almost what people are going to say before they say it! This makes the decoding process proceed very rapidly in large chunks.