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

VOA: special.2010.07.27

Here's another example. A more serious example.

还有一个稍显严肃的例子。

How long课堂 - SpeakingMax英语口语达人

A more recent side effect of Ambien that's quite serious is some people become--have the compulsion while they're sleeping to go driving, which is not good.

最近发现安必恩一个挺严重的副作用,有些人睡觉时,会有梦游驾车的冲动，这可不是好事。

耶鲁公开课 - 心理学导论课程节选

However,fifteen percent of patients develop a more serious condition.

VOA: special.2009.05.26

Even if U.S.economic output expands in 2010 and more Americans head back to work, both critics and supporters of the president say the nation faces a more serious challenge to future economic viability: a rapidly growing deficit and a national debt estimated at more than $12 trillion.

VOA: standard.2010.01.15

And it's a serious issue. And we hope that we can be able to provide more funding to combat suicide."

VOA: special.2009.11.13

But the effects might be more serious than just a red face.

VOA: special.2009.06.23

Among the album's 14 tracks are a few that deal with more serious themes than his previous releases.

VOA: standard.2009.09.03

"For the health sector, it will be to be ready to cope with a disease, which will spread in areas where they do not spread or which may become more serious,".

VOA: standard.2009.08.30

He also offered some tough talk. "I emphasized that this has to be a point in time in which we begin to write a new chapter based on improved governance, a much more serious effort to eradicate corruption, joint efforts to accelerate the training of Afghan security forces so that the Afghan people can provide for their own security,".

VOA: standard.2009.11.02