This sentence is actually correct. All verb tenses, punctuation, and conjunctions are properly used. "Was fired" (past passive), "was often late" (past habitual), and "was poor" (past state) are all appropriate.

The subject "Each" is singular, so the verb must be singular: "has submitted" not "have submitted." "Each of the candidates has submitted" is correct. "Their" is acceptable as a singular they.

This sentence contains a double negative. "Doesn't know nothing" means she knows something. Correct versions: "She doesn't know anything" or "She knows nothing." Double negatives are non-standard in English.

In third conditional sentences, use "if I had known" not "if I would have known." The correct structure is: If + past perfect (had known), + would have + past participle. "Would have" only appears in the result clause.

"The number of" is singular, requiring a singular verb: "has increased." "A number of" would be plural ("have increased"). "The number" refers to the specific count as a single entity.

After the preposition "between," use object pronouns: "me" not "I." Correct: "Between you and me." "Between you and I" is a common hypercorrection. Prepositions always take the object case.

After "recommend," use the gerund or a "that" clause, not the infinitive. Correct: "He recommended taking the training course" or "He recommended that I take the training course." "Recommended me to take" is incorrect.

With "neither/nor," the verb agrees with the nearest subject. "Assistants" is plural, so the verb should be "were." Correct: "Neither the manager nor his assistants were available." If the order were reversed, "was" would be correct.

Double superlative error. "Most smartest" combines "most" and "-est." Correct: "the smartest" or "the most intelligent." For short adjectives (smart), use "-est." For longer adjectives (intelligent), use "most."

The phrase is "despite" (no preposition) or "in spite of" (includes "of"). "Despite of" is incorrect. Correct: "Despite the rain" or "In spite of the rain." "Despite" already contains the meaning of "in spite of."

This sentence is correct. Singular "they" (their/they) is now standard English for referring to a singular antecedent of unspecified gender (Each employee... They must). No error exists in this sentence.

This sentence is redundant. "The reason why... is because" repeats the idea of causality. Correct: "The reason he was late is that his car broke down" or "He was late because his car broke down." "Is because" is incorrect after "reason."