1.When they are working on a tough problem they often seem to disappear completely until they've figured it out.
当他们遇到一个棘手的问题，他们常常会完全消失似的，直到他们已经解决了问题。
2.They had overcome one tough problem after another before working out this sort of energy-saving lamp.
我们在制造这种节能灯时克服了一个又一个难题。
3.Photo-Realistic Rendering of large-scale scene is always a tough problem in computer graphics community.
并行方法是绘制大规模复杂场景的真实感图形的有效手段之一。
4.How to make students accept and understand the executable course of digital logical circuit easily has been a tough problem in teaching .
如何在教学实验中使学生更好地学习数字逻辑电路和对已有的数字逻辑电路进行验证是一个比较繁琐的问题。
5."This is a very, very, very tough problem, " he said, when asked if the disaster would end soon.
当他被问及原油泄漏事件是否能够尽快处理完毕时，他也谈到，这是个非常棘手的问题。
6.Queuing for service at the network is a familiar phenomenon and also an urgent tough problem to be solved.
在营业厅服务系统中，排队是一个常见的现象，也是一个令管理者头疼的问题。
7.By no means was he able to handle the tough problem.
他没有办法处理这个棘手的问题。
8.Victoria Griffith reminds us that knowledge transfer is still a tough problem although we are living in the "knowledge era" .
维多利亚·格里菲斯提醒我们，我们虽然生活在“知识时代”，知识传送仍是一个难题。
9.But in current mobile agent systems, malicious hosts problem, namely protection of mobile agent against malicious hosts is a tough problem.
但在目前的移动代理系统中，恶意主机问题，即保护代理免受恶意主机的攻击是很棘手的问题。
10.At present, there exists serious "non-response" problem in sampling survey, and almost all of the survey organizers face this tough problem.
目前，抽样调查中存在着日益严重的无回答问题，几乎所有的调查组织者都面临着这一令人头痛的问题。