这是高中地理题，生成一个讲解视频---**Extraction Content:** As shown in the figure is a schematic diagram of the global longitude and latitude lines unfolded. The dashed line AS in the figure represents the twilight line. Point D is the intersection of the twilight line and the equator. Point D is also the midpoint of GF. The shaded and unshaded parts represent two different dates, the 6th and the 7th. Read the figure and complete questions 10-11. **Diagram Description:** * **Type:** Schematic diagram of global longitude and latitude lines unfolded as a rectangular grid. * **Coordinate Axes:** Horizontal lines represent parallels of latitude; the central horizontal line is labeled 0° (equator). Vertical lines represent meridians of longitude; the left edge is labeled "180W", the right edge is labeled "180E". Other vertical lines are present as grid lines. There are labels "0°" and "90°" indicating longitude difference or potentially another reference. * **Points:** Points labeled A (top left region), B (top right corner), D (on the equator and a dashed line), G (on the equator, left of D), F (on the equator, right of D), S (bottom central region). D is the midpoint of GF. * **Lines:** Dashed line AS runs diagonally from the top left to the bottom center, passing through D. Horizontal and vertical grid lines are present. The line representing the equator is marked 0°. * **Shapes:** The diagram is a rectangle divided by horizontal and vertical grid lines. Shaded and unshaded areas are present, representing different dates. The shaded area is primarily on the left and part of the right side. The unshaded area is in the central part and part of the right side. * **Labels and Annotations:** Labels for longitude "180W", "180E", "0°", "90°". Labels "在西十二" near G and "在东十二" near B likely indicate longitude zones (West 12 and East 12, corresponding to the 180° meridian). Handwritten annotations include scribbles, checkmarks, and crosses near options for questions 10 and 11. **Question 10:** 此时 F 点的地方时为 A. 7 日 21 时 B. 6 日 9 时 C. 6 日 21 时 D. 7 日 9 时 **Question 11:** 下列关于该图的说法, 正确的是 A. AS 线为晨线 B. BC 所在经线为国际日界线 C. 赤道上西半球的白昼长于黑夜 D. 赤道上东西半球的白昼长度之比为 23:13