大问题的英文：
great problem
large problem

参考例句：

Hey! Today 's paper says that water resource will be a big problem in large city like Shanghai. Is that so?
嗨!今天的报纸说水资源将成为上海这种大城市的一个大问题，这是真的吗?

The experiment went disastrously wrong, ie progressed in an unexpected way with very unpleasant results
这个试验出了大问题

Terrorism continued as a major subject of public concern.
恐怖活动仍然是公众关心的大问题。

The safe disposal of nuclear waste is a major problem.
安全处置核废料是个大问题。

A big snag is a shortage of qualified staff.
缺乏合格的员工是一个大问题。

The depletion of underground water supplies is a big problem.
地下水源的枯竭是个大问题。

Tunnelling under the English Channel is a big proposition.
在英吉利海峡海底凿隧道是一个大问题。

It is a big problem to find ways for the coastal areas to assist the inland areas.
沿海如何帮助内地，这是一个大问题。

Air pollution is also a big problem in very large cities,especially in developing countries.
在大城市，空气污染同样是个大问题，尤其是在发展中国家。

The group's lack of enterprise is a big problem.
那个团队事业心的缺乏是个大问题。

great是什么意思：
adj. 巨大的；很多的；重大的；伟大的；优异的；极好的；非常的
n. 大师；大人物，伟人

A great talker is a great liar
言多必妄

Great hopes make great man
伟大的抱负造就伟大的人物

Great hopes make great men
伟大的希望造就伟大的人物

problem是什么意思：
n. 难题，困难；逻辑题

It was a complex problem.
这是一个复杂的问题。

Is the problem that easy?
问题有那么简单吗?

This is a prime problem.
这是一个有关质数的问题。

large是什么意思：
adj. 大的，宽大的；多的，多量的，多数的；广博的；广泛的
adv. 大，大大地；夸大地

The shop was mobbed by a large crowd.
这家商店遭到一大群人的袭击。

This picture attracts a large audience.
这部电影吸引了很多观众。

The concert drew a large audience.
音乐会吸引了大量的观众。