请解题---1. 如图 1, 把一块含 30° 的直角三角板 ABC 的 BC 边放置于长方形直尺 DEFG 的 EF 边上.图 1图 2备用图(1) 【特例初探】如图 2, 现把三角板绕 B 点逆时针旋转 n°, 当 0<n<90, 且点 C 恰好落在 DG 边上时, 请求 ∠1+∠2 的度数.(2) 【技能提升】在 (1) 的条件下, 若 ∠2 比 ∠1 的一半多 90°, 求 n 的值.(3) 【综合运用】如图 2, 现将射线 BC 绕点 B 以每秒 5° 的转速逆时针旋转得到射线 BC', 同时射线 QA 绕点 Q 以每秒 4° 的转速顺时针旋转得到射线 QA', 当射线 QA 旋转至与 QB 重合时, 则射线 BC、QA 均停止转动, 设旋转时间为 t (s). 在旋转过程中, 是否存在 QA' // BC'? 若存在, 求出此时 t 的值; 若不存在, 请说明理由.---**Chart/Diagram Description:****Figure 1:*** Type: Geometric diagram.* Main Elements: * A right-angled triangle ABC with ∠C = 90° and ∠A = 30°. * A rectangle DEFG (representing a ruler). * Side BC of the triangle is placed along the side EF of the rectangle. B is on EF, and C is on EF. * Vertex A is above the rectangle. * Line segment AQ intersects DG at Q. * Angle ∠1 is formed between line segment AQ and the line DG. * Angle ∠2 is formed at vertex C, with one side along AC and the other side pointing upwards, perpendicular to EF. Specifically, ∠ACB is the right angle of the triangle. It seems that line segment AC intersects DG at point Q. It looks like ∠1 is ∠AQD and ∠2 is ∠CQG. There is also a point Q on AC. Line segment BQ is drawn. It is labeled that ∠ABC is implied to be 60° (since ∠A=30° and ∠C=90°).**Figure 2:*** Type: Geometric diagram.* Main Elements: * The same initial setup as Figure 1. * The triangle ABC has been rotated counterclockwise around point B by an angle n°. * The rotated triangle is shown. Point B remains on EF. * The rotated point C, labeled C, is now on the line DG. * The rotated point A, labeled A, is above the rectangle. * Angles ∠1 and ∠2 are labeled. ∠1 appears to be the angle between AB and DG. ∠2 appears to be the angle between AC and DG. The labeling of ∠1 and ∠2 is the same as in Figure 1, but their positions relative to the rotated triangle should be considered based on the question context. In Figure 2, point C is on DG. So ∠2 is likely ∠BCG where C is the rotated point C, or an angle related to the line AC and DG. Based on question (1), ∠1 and ∠2 are angles related to the rotation. Let's assume ∠1 is the angle between AB and DG and ∠2 is the angle between BC and DG, or possibly angles related to point C landing on DG. Given the context of rotating triangle ABC around B, and C landing on DG, and asking for ∠1+∠2, referring to the labels in the diagram itself, ∠1 is the angle between the line segment AB and the line segment DG, and ∠2 is the angle between the line segment BC and the line segment DG. More precisely, ∠1 is the angle above DG, and ∠2 is the angle below DG, both formed at the intersection point on DG with AB and BC respectively. However, the labels ∠1 and ∠2 are shown near the vertices of the triangle in Figure 2. Let's re-examine. In Figure 2, point C is on DG. ∠1 is located near vertex A and line AB intersecting DG. ∠2 is located near vertex C and line BC intersecting DG. * Let's interpret the labels as shown. In Figure 2, the triangle ABC is rotated around B. The original BC was on EF. The new C is on DG. Since EF is parallel to DG, the angle of rotation n° is the angle between BC (original position) and BC (new position), i.e., ∠CBC = n°. * In Figure 2, ∠1 is labeled as the angle formed by line AB and line DG. Specifically, it seems to be the angle between AB and DG at their intersection point, let's call it P. ∠1 = ∠BPD. * ∠2 is labeled near vertex C. Since C is on DG, ∠2 seems to be an angle related to BC and DG. Looking at the figure, it seems that ∠2 is the angle between BC and DG at point C. Specifically, ∠BCG.**备用图 (Spare Diagram):*** Type: Blank space.* Purpose: Provided for rough work or additional diagrams if needed.