Grammar and syntax errors can be harder to detect than spelling and punctuation mistakes, yet they are more serious as they can alter the meaning and structure of your sentences and paragraphs. To avoid those errors, you should have a strong understanding of the basic rules of English grammar, such as subject-verb agreement, verb tense, pronoun reference, and sentence types. Additionally, you should be aware of common grammar and syntax errors, such as fragments, run-ons, and dangling modifiers. Fragments are incomplete sentences that lack a subject, a verb, or both; for example "Because of the rain." To fix fragments, you must add the missing elements or connect them to a complete sentence with a conjunction or punctuation mark. Run-ons are sentences that contain two or more independent clauses without proper punctuation or conjunctions; for instance "She loves reading he loves writing." To correct run-ons, you must separate the clauses with a period, semicolon, or comma and conjunction; or use a subordinating conjunction to make one clause dependent on the other. Lastly, dangling modifiers are words or phrases that modify a word that is not clearly stated in the sentence; for example "Walking to the store, the weather was nice." To fix dangling modifiers, you must place the modifier next to the word it modifies or add the missing word to the sentence.