A:等于NA
B:小于NA
C:大于NA
D:无法判断
完型填空。
I am 1English boy. My 2is Mike. I am twelve. My sister's name is Ann and we are students. My mother3a teacher. She's a Chinese teacher. My brother's name is Jim. He's five.4 father isn't here. He's 5Xinjiang. I think my family is a good one.
下列式子中32a,1x+y,aπ,4a2﹣b,3a-2b5中整式的个数是( )
下列地理现象能说明地球自转的是( )