某企业只生产一种产品，单价30元，单位变动成本18元，固定成本为3000元，满负荷运转下的正常销售量为400件。以下说法中，正确的有（）。

A.在自变量以销售额表示的边际贡献式本量利图中，该企业的变动成本线斜率为12

B.在保本状态下，该企业生产经营能力的利用程度为62.5%

C.安全边际中的边际贡献等于1800元

D.安全边际率为37.5%

You want to know what the safest place for children 77．______
is in the car The experts say the back seat is the safest for 78．______
them. The back seat is farthest away off the force of a head- 79．______
on collision(迎头撞击), which can lead serious injuries. 80．______
If your child is below 8 and weighs no more than 85 81．______
pounds, it is necessarily to fit your car with a safety seat. 82．______
Moreover, the safety seat must be held in place of on the83．______
car’s back seat. If your child do need your attention while 84．______
you driving, don’t look back with only one hand on the 85．______
wheel. You’d better stop the car. 86．______