A:滥伐森林
B:水体污染
C:南极冰川融化
D:臭氧层破坏
The job of the speaker
A____
The first thing that you have to do
Write a ____about yourself
The third thing to do
Read the paper to the____
Things you can't do
Don't ____that will make everyone laugh.
The time to get everything ready
____
人的体细胞中一对基因(Aa)在一对染色体上,下列叙述不正确的是( )