1. He believes very strongly that children need the experience of school to ensure the quality of being taught the basics and being examined.
    他深信孩子们需要在校学习的经历，以保证基础知识的学习和考试的质量。

2. And to ensure the populations were "pure", the study was confined to groups that were in their present locations as of 1492, before the first major movements from Europe began — in effect, a genetic photo of the world when Columbus sailed f
    为了确保种群的"纯正"，这项研究将对象限定于其目前的生活区域仍与1492年以来相同的那些群体，即在来自欧洲最初的大规模迁移之前。这实际上就是一幅真实的哥伦布驶向美洲时期的世界人口基因分布图。

3. Let's hope our educators answer students' cries for career education, but at the same time let's ensure that students are prepared for the day when they realize their shortsightedness.
    我们希望我们的教育工作者能满足学生对职业教育的渴求，但与此同时，我们也要确保学生能为他们认识到自己目光短浅的那一天作好准备。

4. If you're going to spend a lot of time with a particular driver, plan ahead to ensure the day will go smoothly.
    如果你打算和某一个司机相处好长一段时间，事先要计划好，以保证当天顺利。