Regularly reading in English is one of the best ways of improving your level in the language. It not only improves your knowledge of vocabulary and grammatical structures in English, but the more times you see words/phrases and grammatical structures being used, the more likely you will both understand and use them yourself.
Below is a link to an article called 'What actually caused the dinosaurs to become extinct?' which is right for people with an upper-intermediate level of English.
Before you read the article, I recommend that you read the below 'Article summary'. Knowing what the article is about will make it both quicker and easier to read.
This article explains a theory that the extinction of the dinosaurs was caused by an asteroid hitting the earth. It explains both how scientists came up with the theory and how the impact of the asteroid caused very large amounts of soot (very small particles normally created by the burning of coal, wood or oil) to be released into the atmosphere which eventually killed the dinosaurs.
Type of vocabulary used: Science, Climate,