Yes, they are. See?
的正确意思要看上下文,
不过可以这样翻译：
是的,他们/它们是, 你看到了吗?
比如：
A: Are these birds or airplanes?
B: These are airplanes.
A: Are you sure?
B: Yes, they are. See? They have vapor trails.
希望帮到了你.