退运后的设备状态包括()。
A.现场留用
B.库存备用
C.待报废
D.退出运行
参考答案:A, B, C
选择合适的单词填空。
1. Where ____________ (is / are) the shoes?
2. I want ____________ (buy / to buy) a book.
3. This department store ____________ (has / have) toys and books.
4. Let's go ____________ (shop / shopping) today.
5. ____________ (What / Where) do you want to buy?
因式分
(1)3a-9
(2)a2+6a+9
(3)-16x+x3
(4)(x-1)(x-3)+1.