| 摘要 |
PCT No. PCT/CH85/00177 Sec. 371 Date Nov. 18, 1987 Sec. 102(e) Date Nov. 18, 1987 PCT Filed Dec. 19, 1985 PCT Pub. No. WO87/03990 PCT Pub. Date Jul. 2, 1987.In order, for example to produce solution noting/check-out sheets, such as are used in correspondence courses, so that a sheet of writing paper can be written on externally only up to the time when information concerning the correct solution to the problem is made known to the person writing on it, a sheet of writing paper comprises two sheets (1, 3) joined together on three edges (15) and an intermediate sheet (5). The intermediate sheet (5) ensures that when the paper is written on in a writing area (17) the information is transferred to one of the sheets (1, 3). An adhesive place (11) is provided between the sheets (1, 3) which does not adhere to the intermediate sheet (5) but indissolubly binds the two sheets (1, 3) when the intermediate sheet is removed. Located in an information area (19) is the correct solution, which cannot be seen while an intermediate sheet is inserted (15), so that the user can learn the correct solution only after the intermediate sheet (5) has been withdrawn, at a moment when the adhesive place (11) is already activated and therefore any correction and/or completion in the writing area (17) is rendered impossible. |
