五个有理数的积为负数,则这五个数中正因数的个数是 ( )
A:2个
B:1,3或5
C:0,2或4
D:无法确定
When playing football, Tom had his leg b____and was sent to a hospital.
24+6=____
9×3=____
6×5=____
72-4=____
38-8=____
36÷4=____
56÷7=____
4×9=____
____