A:6
B:7
C:8
D:9
图a处流入的血液是__________,d处流入的血液是__________.( )
Ann sat there for____ ____two hours.
用简便方法计算,写出主要计算过程.
8.37×7.2+8.37×2.8=____
设a,b,c为正数,求证:a2b+b2c+b2a≥a+b+c ..