A limited partnership refers to a partnership composed of general partners and limited partners. The general partners bear unlimited joint and several liability for the debts of the partnership, and the limited partners are responsible for the debts of the partnership to the extent of their contribution. Based on the above definitions, Which of the following are limited partnerships:. ['A and B are partners of the partnership, and A assumes unlimited liability for the debts of the partnership caused by the fault of A; B shall be liable to the extent of its property share in the partnership.', 'Debt to the partnership. All partners have unlimited liability.', "The company's external debt is borne by the company with its own capital, and has nothing to do with the personal property of A or B.", 'For a partnership, A contributes 20,000 yuan and B contributes 200,000 yuan. A participates in the daily operation and management of the enterprise, and B does not participate in the management. The post-partnership business has a loss and external debts amount to more than 1 million. Responsibility, B is limited to 20.']