Hi Moonyoung. Welcome aboard, and congratulations on getting this far. I'm going to divide up this critique in the same way as the lesson, so let's get right into it.

Lines

I'm seeing a fair amount of wobble in your linework in general, especially in the first couple of exercises. The good news is that this means you are already starting to overcome this. The bad news is, it means you still need to take the core principles of markmaking to heart. For now, even though it might be quite time consuming, focus on ghosting out your lines as many times as it takes for you to comfortably make a quick, smooth motion along the right trajectory. When the time comes to actually draw. Confidet strokes are better than accurate ones for now, and accuracy will come with time. The starting points of your Superimposed Lines are also a little frayed, which we want to avoid (after all, the starting point is the one part of the line you really can take time over). On the other hand, I'm not seeing a lot of arcing in your lines, which is a good sign, and you have clearly performed the exercises as instructed. While you might benefit from more practice over time, you did fine in this section overall.

Ellipses

You are drawing through your ellipses twice, which is good. Again, I see signs of insufficient ghosting in the shape of a fair few of these, and many of the ellipses in your Ellipses in Boxes overlap one another, or the boundaries of the frame. This latter problem is an issue of accuracy, but still speaks to a lack of time spent before putting pen to paper. Your Funnels look quite good, though it might be nice to see a little more differentiation in the angles of the ellipses from centre to side, and they could be positioned a little better relative to the minor axis. Remember it should cut them neatly in half. I know this just reads like a series of flaws, but atteding to those is how we improve. You have again completed the exercises correctly and show clear growth as you go on.

Boxes

First of all, I can see that you are properly drawing through your boxes everywhere you were instructed to do so. Good work. You also applied the line correction method properly in your Rough Perspective exercise. I can see where you've gone wrong on your Rotated Boxes; it's important to keep the corresponding corners close to those of the adjacent boxes. Don't be afraid to draw 'behind' things you've already drawn, in just the same way as you draw 'inside' boxes when you draw through them. These exercises are to help you begin to understand how forms relate to each other in 3D space, so it's common for the drawings to get very busy, and this is nothing to worry about. You also have some sides not slanting 'away' from the viewer as they rotate away from them as seen in this image: https://d15v304a6xpq4b.cloudfront.net/lesson_images/d73eea49.jpg). This is something to bear in mind in the future. Your grip on perspective overall is not quite there yet, but fine for this stage. I can also see that you've opted to add some line weight to show lines at the front, which is good, but the same points about line confidence I madde earlier apply here. Overall good work again.