Although scientific text typically has a more complex structure and vocabulary than fiction or text written for the general public, its message should still be clear and concise. One way to ensure this is to use correctsentence structure. If a scientific text is hard to understand, it may be because the sentences do not follow the expected structure and have a confusing number of commas or short phrases. This article provides a short overview of the four main ways that English sentences can be structured, with accompanying examples and exercises for each type.