用所给动词的适当形式填空。

1.          (smoke) is bad for health, everyone should give it up.

2. Be        (care)! The traffic is too heavy.

3. The little boy____ (mislead) us we can't find the hotel at all．

4. Some ads are very____ (confuse),for they can mislead us．

5. The seat is too hard. It makes people        (comfort)．

有关体细胞突变的后果，下面哪项是错误的（）

A.可使体细胞发生不正常的分裂

B.可使体细胞发生不正常的增生

C.不具有传递性质

D.是癌变的基础

E.也是致畸的基础