This document summarizes the structure and skills tested in the Structure and Written Expression section of the TOEFL exam. It consists of 40 multiple choice questions over 25 minutes. The section tests skills related to grammar, including ensuring sentences have subjects and verbs, proper use of object of prepositions, appositives, coordinate connectors, parallel structure, past participles, comparatives and superlatives, verb forms after modals, active and passive voice, countable vs. uncountable nouns, and proper use of pronouns. The document provides examples and explanations for each grammar skill tested.