对于多细胞生物而言，下列有关细胞生命历程的说法正确的是（）

A.细胞分化导致细胞中的遗传物质发生改变

B.细胞癌变是所有细胞都要经历的一个阶段

C.细胞衰老时细胞呼吸的速率减慢

D.细胞死亡是细胞癌变的结果

句型转换。

1. There is only one radio in the box. (对画线部分提问)

    How_____ _____ _____there in the box?

2. You can't feed the birds in the park. (改为祈使句)

     _____ _____birds in the park.

3. Lily has some toys in her locker. (改为否定句)

    Lily_____ _____ _____toys in her locker.

4. This is Andy and Millie's ball. (对画线部分提问)

    _____ball is this?

5. There are not any goldfish in the fish tank. (同义句)

    There are_____goldfish in the fish tank.