You can be in deep water, for example, if you invest in stocks without knowing anything about the stock market.

VOA: special.2009.05.10

If you knew only the third derivative of the function, you can have something quadratic in t without changing the outcome.

如果方程里有三阶导数,你就可以引入一个二次项,但是结果却不会变

耶鲁公开课 - 基础物理课程节选

If you feel exposed without a text book, you really have to have a textbook, John actually I'm going to reuse that word, John, at least suggest it, on the course website.

如果你觉得没有教科书就缺乏安全感的话，那你真的需要一个了，其实我应该重新使用这个词儿，至少是建议，你能在课程网站上找到。

麻省理工公开课 - 计算机科学及编程导论课程节选

If they feel positive about you, if you personally endorse it without being dogmatic, and if you provide real-world examples or stories of how this process has been helpful in similar situations, people will be more likely to be interested in and open to your message.

FORBES: How To Get People To Agree With You

The trust carefully controls the number of visitors arriving by car, by insisting they book ahead at least a couple of days in advance - if you drive in without a booking you are likely to be turned away.

BBC: Devon - Greenway success is no mystery

If you know you're making a decision whether you go without a meal so your kids eat, if you know you have to make these types of choices, put your pride aside.

NPR: Escaping Hunger: One Man's Story