this course is computer engineering drawing

3. Short answer questions (4 questions in total, 10 points for question 1, 6 points for question 2 and question 3, 8 points for question 4, 30 points in total) (1). It is often necessary to use some toolbars that are not displayed in the drawing area in the drawing process. Try to explain how to open the Drawing toolbar, modify toolbar, object snap toolbar, layer toolbar and annotation toolbar. (2). What is the difference between the left box selection method and the right box selection method when selecting objects. (3). The operation of drawing bisectors on a straight line has been completed, but there is still only a straight line on the screen, and the bisectors are not displayed, What's the reason? (4). What are the commands for creating blocks and external blocks? What's the difference between the two