Use "that" in a restrictive clause, to specify a particular thing you are talking about, and use "which" in a nonrestrictive clause, to provide additional information about something. The "which"...
'Not' is an adverb, and is used to make a verb negative. (not + verb) Example with the verb 'to like': Positive: I (do) like chocolate. Negative: I do not like chocolate. Example with the verb 'to...