For the slow-growing pig the same maintenance cost is spread over half the productive gain. 对于生长慢的猪来说同样的维持消耗值被分摊到只有生长快的猪的一半的增重上。
Scientists looked at twins to take into account familial or genetic factors affecting smoking and weight gain, Saarni said. 萨尼说，科学家们选双胞胎作为目标是因为考虑到家族和遗传因素会影响吸烟和增重。
