根据下列短文内容，在短文的空格处填上一个恰当的词，使短文完整、通顺。

    This is a picture of a classroom. The classroom is big and  because we clean (打扫) it every day. You can  a teacher's desk, five desks and six chairs, you can see a boy and a girl, . Three books  on the teacher's desk. A pencil box is on the desk. Two pens  two rulers are in the pencil box. A schoolbag  under the chair. The girl is Lucy. She is twelve. The boy is Mike. He is thirteen.  are in Class 2, Grade 1. They are friends. They  their teacher Miss Grace because she is kind to them.