The Mystery of the Missing Ring During the Trip

A teacher is traveling with a group of people, and everyone brings a travel bag. At night, everyone stays together in a tent. On the second morning, a lady wakes up and finds the ring on her hand is gone. The ring was still on her hand right before she went to bed last night. Everyone questions each person one by one to find out who took the lady's ring. When they asked the teacher, he did not answer a single word. So everyone suspects that the teacher took the ring. They searched the teacher's entire body and his travel bag, but did not find the ring. Later, the teacher gave everyone a hint: the ring is not lost, it is still inside the tent. But everyone searched the whole tent and still could not find the ring. It is known that the teacher never lies, and no one left the tent last night.