If someone borrows money and doesn't pay it back, can they sue?

Referring to Article 42 of the Law on Public Security Administration Punishment, anyone who commits one of the following acts shall be detained for not more than five days or fined not more than five hundred yuan; If the circumstances are serious, he shall be detained for not less than five days but not more than ten days, and may also be fined not more than 500 yuan: (1) writing threatening letters or threatening the personal safety of others by other means; (2) publicly insulting others or fabricating facts to slander others; (3) fabricating facts, falsely accusing and framing others, and attempting to subject others to criminal investigation or public security administration punishment; (4) Threatening, insulting, beating or retaliating against witnesses and their close relatives; (5) sending obscene, insulting, intimidating or other information for many times to interfere with the normal life of others; (six) voyeurism, sneak shots, eavesdropping, spreading the privacy of others. Article 293 of the Criminal Law Whoever commits one of the following acts of stirring up trouble and disturbing social order shall be sentenced to fixed-term imprisonment of not more than five years, criminal detention or public surveillance: (1) beating others at will, if the circumstances are bad; (two) chasing, intercepting, insulting or intimidating others, and the circumstances are bad; (three) extortion or arbitrary damage, occupation of public or private property, if the circumstances are serious; (4) Causing serious disorder in public places. Whoever gathers people for many times to commit the acts mentioned in the preceding paragraph and seriously undermines social order shall be sentenced to fixed-term imprisonment of not less than five years but not more than 10 years and may also be fined.