It's really foolish ________ what he says.
A:for him to trust
B:of him to trust
C:to him trusting
广告费用X (万元)
1
2
3
4
5
6
7
销售额y (百万元)
2.9
3.3
3.6
4.4
4.8
5.2
5.9
根据表可得回归方程y=bx+a中的a为2.3,根据此模型预报广告费用为12万元时销售额为____万元.
加热时间/min
0
8
9
10
11
物质的温度/℃
40
42
44
46
48
50
53
56
如图所示是盒装牛奶,它的体积为____ cm3。若该牛奶的密度是 1.2×103kg/m3,合____ g/cm3,则牛奶的质量为____ g。喝掉一半后,牛奶的密度将____ (选填“变大”、“变小”或“不变”)。