A：②④
B：④
C：③
D：③④
世界上面积最大的大洲是（ ）
下列有关鉴别二氧化碳、氧气的方法错误的是（ ）
读一读，选一选
____ Is your father here today? A. No, I don't.
____ What does your mother do? B. He's a businessman.
____ Do you want to be a head teacher? C. No. He's in Australia.
____ What does he do? D. She's a head teacher.
若关于x的分是方程2x-3+x+m3-x=2有增根，则m的值是（ ）
