A sketchpad is a stack of paper fastened together for drawing — first tries, quick pictures, lines you may later throw away. The sheets are usually glued or stapled along one edge, like a notepad, so you can flip them or tear one off. Artists, designers, and children all use one. In shops you will also see sketchbook, and in ordinary talk people treat the two as almost the same. Though actually, a pad often feels like loose sheets stuck at the top, while a book is bound more firmly; nobody will make a fuss. The word is simply sketch plus pad, and it is ordinary, not fancy. You draw on a sketchpad. You do not “sketchpad” as a verb in standard English. It is paper, not a computer tablet, even though so many “pads” now are screens.

素描本、速寫本（紙本；不是畫板，也不是平板）