[formal] The correct answers can be found at the bottom of page 8

If the noun is singular, use is

What is proper in an informal context is not always proper in a formal context

until he sees himself, creeping down the hall toward the bedroom thinking the intruder is still in here

Reverso detects and corrects all types of grammar and spelling mistakes: wrong verb tenses, lack of agreement between subject and verb, incorrect prepositions, confusion between words with similar spelling, typos and punctuation errors