The infinitive form of a verb is the verb in its basic form. It is the version of the verb which will appear in the dictionary. The infinitive form of a verb is usually preceded by to (e.g., to run, to dance, to think). The infinitive form is not always preceded by to. - Google result for "What is an infinitive"
Third-person-singular. (grammar) The form of a verb used (in English and other languages) with singular nouns and with the pronouns he, she, it and one (their equivalents in other languages). "Is" is the third-person singular of "to be". The pronouns he, she, it and one (their equivalents in other languages). - Google result for "third person singular"
I'm having trouble with the о sound because she sounds like чел-ahhee-век Is that the sounds around the o making it a dipthong? OK, I think I found some hints on this pronunciation on a YouTube video: https://www.youtube.com/watch?v=roevsN1zBl4 I think the soft/hard consonants are what is making me nuts.
Words like "bread", "rice", or "people are uncountable or mass nouns. They can never have a/an before them.