方位介词 in, on, under — 英语阅读题

Read the passage and answer the question. This is our classroom. Look! The teacher's desk is near the window. A big book is on the teacher's desk. My schoolbag is in the desk. Where is my pencil case? It is not on the desk. It is not in the schoolbag. Ah, it is under the chair! Two rulers are in the pencil case. My friend Sam's ball is under the teacher's desk. We keep our classroom clean and tidy. Question: Where are the two rulers? Please answer in a short sentence.