语法与词汇 10.The custom is______in the belief that a new pregnancy—through its detrimental effect on breastfeeding—would endanger the mother's health.

【正确答案】 B

【答案解析】本题中，B项“observe遵守”符合题意。其他三项“celebrate庆祝；view观察，看待，认为；present展示”都不正确。