Excessive addition of pr video cannot be placed between two pieces of material. If the transition effect can only be placed at the beginning and end of the video, but not between videos, please drag the transition effect to the desired position first. At this time, even if the effect is not between videos, it doesn't matter at the end of the previous paragraph or the beginning of the next paragraph. At this time, click on the small box just put in, and the control of the transition effect will appear in the upper left corner of the editing layout. Select the center cut in the alignment drop-down option to place the transition effect in the middle of the two videos.