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

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

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

"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