S: (v) persevere, persist, hang in, hang on, hold on (be persistent, refuse to stop) "he persisted to call me every night"; "The child persisted and kept asking questions"
S: (v) obstinate (persist stubbornly) "he obstinates himself against all rational arguments"
S: (v) ask for it, ask for trouble (persist with actions or an attitude despite the probability that it will cause trouble) "He is asking for trouble with his behavior"
S: (v) plug, plug away (persist in working hard) "Students must plug away at this problem"