He resigned because he saw his resignation as the only way of solving a serious problem Jackson faced.

VOA: special.2009.01.01

And off he goes, and he sulks in his tent for the next nine books, and this turns out to be a serious problem for them.

然后他真就走了,他回到自己的帐篷收拾东西,他这一走 问题就大了

耶鲁公开课 - 古希腊历史简介课程节选

So we learned the very first time that in the Prisoner's Dilemma communication per se won't help, but in the coordination problem, which could be just as serious socially as a Prisoner's Dilemma, in a coordination problem it may well help.

在第一讲里我们就学到了,在囚徒困境中沟通不起作用,但是在和囚徒困境具有,同样重要社会意义的协和谬误中,交流却能够起到作用

耶鲁公开课 - 博弈论课程节选

This could be a serious problem. The shield protected the spacecraft from burning up from the extreme heat of re-entering the Earth's atmosphere.

VOA: special.2009.06.17

Some Arizona officials blame smugglers for a serious problem with kidnappings in the Phoenix area.

VOA: special.2010.07.03

But there was a serious problem after the landing.

VOA: special.2009.06.17

Pierce agreed that Kansas was a serious problem.

VOA: special.2009.04.30

It was a serious problem with Apollo Thirteen.

VOA: special.2009.07.22

Malnutrition remains a serious problem for India.

VOA: special.2010.05.12

Consultant Anholt calls it a serious problem.

VOA: standard.2009.11.05

And,there is a serious problem when you use the term 'regime change' that you might encourage people to demonstrate,or to act in ways, where we can do absolutely nothing to protect or encourage them."

VOA: standard.2010.06.11

Untreated heat stress can lead to a more serious problem called heat exhaustion.

VOA: special.2010.07.27

He calls it "a very serious problem in the United States."

VOA: special.2010.06.14

He said it is a serious international problem that should be addressed broadly and can not be solved entirely by military means.

VOA: standard.2009.04.13

"Human trafficking is a very serious problem in the United States."

VOA: standard.2010.05.24

In an attempt to show they are serious about supporting a solution to the protracted Cyprus problem, Britain has renewed an offer to cede about half the territory of its bases in Cyprus.

VOA: standard.2009.11.11

"Now,the degree which will have on the peace process and other things which are sort of the hard facts of the Middle East,is something else, altogether,as obviously there is a very serious problem with the Israeli government and so on.

VOA: standard.2009.05.09