Transparency is a relative concept. We say that if light can pass through an object, it can be called transparency. For example, beer bottles are green, but they are also transparent. Therefore, in order to distinguish, we must have a transparent concept. The higher the transparency, the more light passes through and the less light is reflected. Although glass is transparent, its transparency is limited, so there is still light reflected back. Air is much more transparent than glass, so you can't see the reflected light at close range.