Everyone should be careful to use a singular pronoun with singular nouns in their writing. Place pronouns as close as possible, especially in long sentences, as of 10 or more words, to their antecedents. Writing carefully, dangling participles must be avoided. If any word is improper at the end of a sentence, a linking verb is. Write all adverbial forms correct.
Verbs has to agree with their subjects, and the adverb always follows the verb.
This sentence no verb. Which is not a complete sentence, but merely a subordinate clause. A preposition is something you should never end a sentence with. And don't start a sentence with a conjunction.