A：①②③④
B：②③
C：②③④
D：①②③
“野火烧不尽，春风吹又生”，说明生物所具有的特征是（ ）
将左边和右边的句子连成对话。
①Is this your bed? ____ a. Hi, Joe.
②Are these your pens? ____ b. No, it isn't.
③Your book is nice. ____ c. Thank you.
④Hi, Peter. ____ d. Six yuan, please.
⑤How much are they? ____ e. Yes, they are.
导致细胞癌变的致癌因子主要分为：物理致癌因子，如____ ；化学致癌因子，如____ 、____ ；病毒致癌因子，如____等．
