Each book____broken down into several units.在空白處應該填is,was,ha

題目：

Each book____broken down into several units.在空白處應該填is,was,has還是have?爲什麼?

解答：

填 is
Each book is broken down into several units.
每本書都被劃分到特有的單元.
這是個被動不能用 has,have.這又在說一個現在的狀態,用一般現在時.所以填：is.