(2)① Place the candle at point E, the object distance is less than the focal length, and the convex lens becomes an upright and enlarged virtual image.
② When the candle is at four o'clock: A, B, C and D, the object distance is greater than the focal length, and the convex lens becomes a real image. When the candle is at point A, the object distance is the largest and the image is the smallest. The candle is at point D, with the smallest object distance and the largest image.
(3) point b candle, U > 2f, inverted, reducing the real image, used for cameras and camcorders.
④ When the candle is at point B and point A, the object distance is greater than the focal length, and the convex lens becomes a real image. When the candle flame moves from point B to point C, the object distance decreases and the image distance increases, so the screen moves to the right and a clear image is received on the screen.
The candle is at point C, 2f > u > f, forming an inverted magnified real image, which is applied to slide projectors and projectors. (3) As shown in the figure, when the hour hand is at the upper right, the optical center of the convex lens will converge at the lower left of the screen and the minute hand at the lower right, and the optical center of the convex lens will converge at the upper left of the screen, so the watch is imaged by the convex lens as shown in Figure D. 。
Therefore, the answer is: (1) the same height; ②①e； ②a； d； ③ handstand; Shrinking; Camera (or video camera); 4 right; Fall head; Enlarge; Slide projector (or projector); (3)D。