给我答案---**1. Question Stem:** 4. 如图, 是由 5 个大小相同的正方体组成的立体图形, 它的左视图是 ( ) **Translation of Question Stem:** 4. As shown in the figure, it is a three-dimensional figure composed of 5 identical small cubes. Its left view is ( ) **2. Chart/Diagram Description:** **2.1. Main 3D Figure:** * **Type:** Three-dimensional composite figure (a stack of cubes). * **Main Elements:** The figure is composed of 5 identical cubes. * **Arrangement:** * There are 3 cubes forming a horizontal row at the base. Let's label them C1 (left), C2 (middle), and C3 (right) based on the current perspective. * There is 1 cube (C4) placed directly on top of the leftmost base cube (C1). * There is 1 cube (C5) placed directly on top of the middle base cube (C2). * **Overall Structure:** From a "front" perspective (looking at the side with the longest row of cubes), the figure has three vertical columns: the leftmost column is 2 cubes high (C1+C4), the middle column is 2 cubes high (C2+C5), and the rightmost column is 1 cube high (C3). The object has a depth of one cube unit. **2.2. Options (2D Figures):** The options A, B, C, D are all two-dimensional arrangements of unit squares. * **A.** **Chart Type:** 2D arrangement of squares. * **Main Elements:** 4 squares. * **Arrangement:** 3 squares are arranged in a horizontal row at the bottom. 1 square is placed directly on top of the leftmost square of this bottom row. * **B.** **Chart Type:** 2D arrangement of squares. * **Main Elements:** 4 squares. * **Arrangement:** 3 squares are arranged in a horizontal row at the top. 1 square is placed directly below the leftmost square of this top row. * **C.** **Chart Type:** 2D arrangement of squares. * **Main Elements:** 3 squares. * **Arrangement:** This forms an "L" shape. There are 2 squares stacked vertically on the left. 1 square is placed to the right of, and aligned with, the bottom-most square of the vertical stack. * **D.** **Chart Type:** 2D arrangement of squares. * **Main Elements:** 3 squares. * **Arrangement:** This forms an "L" shape rotated. There are 2 squares stacked vertically on the right. 1 square is placed to the left of, and aligned with, the bottom-most square of the vertical stack. --- **3. Analysis for "Left View":** To determine the "left view" of the 3D figure, we apply standard orthographic projection. Let's define a coordinate system based on the most natural interpretation of the 3D drawing: * The three cubes (C1, C2, C3) at the base are aligned along the X-axis (left-to-right). * The object has a single unit of depth along the Y-axis (front-to-back). * Height is along the Z-axis (up-down). The cubes are located at approximate positions (assuming unit cube size and (0,0,0) for the back-left-bottom point): * C1: (0,0,0) (leftmost base) * C2: (1,0,0) (middle base) * C3: (2,0,0) (rightmost base) * C4: (0,0,1) (on top of C1) * C5: (1,0,1) (on top of C2) The "left view" is obtained by looking at the object from the negative X-axis direction (i.e., from its left side) and projecting its silhouette onto the Y-Z plane. * From this perspective, we are looking at the leftmost vertical slice of the object. * The leftmost part of the object consists of C1 (at (0,0,0)) and C4 (at (0,0,1)). * All other cubes (C2, C5, C3) are positioned further to the right (positive X-direction) and are thus completely obscured by the C1-C4 stack when viewed directly from the left. * The projection onto the Y-Z plane would show a maximum height of 2 units (from C1 and C4) at Y=0 (since all cubes are effectively at Y=0 depth from this viewing angle). Therefore, the **Left View** should be a stack of two squares: ``` [][] ``` This shape consists of 2 squares. **4. Conclusion on Matching Options:** Based on the standard orthographic projection, the rigorously derived "Left View" of the given 3D figure is a vertical stack of two squares. None of the provided options (A, B, C, D) depict a simple stack of two squares. This indicates a potential discrepancy between the problem's options and a standard interpretation of orthographic views, or an implied non-standard orientation/definition of "left view" for this specific question.