The main contents of continuing education for accountants include: (1) accounting theory and practice; (2) Financial accounting laws and regulations; (3) Accounting professional ethics; (4) knowledge of computerized accounting; (5) Other relevant knowledge; (6) Other relevant laws and regulations. The forms of continuing education for accountants can be divided into training and self-study. (1) Training forms include: 1. Training organized by the accounting management organization of the financial department; 2. The training organized by the training unit entrusted by the accounting management institution of the financial department; 3. Business training organized by provincial authorities; 4. Accepting accounting education recognized by the state in ordinary colleges or adult colleges; 5. Other forms of training recognized by the accounting management institution of the financial department. (2) Self-study forms include: 1, business study and job training organized by departments or units themselves; 2. Undertake accounting professional topics and obtain research results; 3, to participate in the superior accounting professional and technical qualification examination; 4. Other forms of self-study recognized by the accounting management institution of the financial department. According to the provisions of China's "Negotiable Instruments Law", a negotiable instrument actor can declare that it is flawed and claim that the negotiable instrument act is invalid under the following circumstances: by means of fraud or coercion or taking advantage of the danger of others, the negotiable instrument act is carried out against the true meaning. Paragraph 2 of Article 21 of the Negotiable Instruments Law stipulates: "A bill of exchange without consideration shall not be issued to deceive banks or other parties to the bill." Non-bona fide bill behavior is also invalid.