We must try to preserve the best of our moral values for our children and grandchildren.

参考答案: B

参考解析: 本句意思是：为了我们的子孙后代，必须尽量保存我们道德价值中最好的部分。句中preserve意为“保护，保存”，例如：It is highly important to preserve the environment.保护自然环境至关重要。四个选项中：prescribe意为“开处方”，例如：What medicine did the doctor prescribe for your illness？医生开了什么药来治你的病？protect意为“保护”，例如：He raised his arm to protect his child from hurt.他伸出手去，保护他的孩子免受伤害。predict意为 “预测”，例如：The earthquake had been predicted several months before.这次地震早在几个月以前就发布了预报。purchase意为“购买”，例如：Tickets must be purchased two weeks in advance.票必须提前两周买。只有选项B同句中画线单词含义接近。