The problem lies in deciding when to intervene.

问题在于决定何时介入。

《牛津词典》

The problem lies in that people still haven't realized the importance of environmental protection.

问题在于人们还没有意识到保护环境的重要性。

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But the problem lies in here!

但是问题就在这里！

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The problem lies in how the U.S. Bureau of Labor Statistics calculates the cost of living.

FORBES: The American Standard of Whining

So the problem lies in countries like China, America and Europe, which all have stable populations.

ECONOMIST: World population: Now we are seven billion | The

But Mr Wallgrave believes the real solution to the problem lies in tackling it in people's country of origin.

BBC: Port uses hi-tech asylum controls