researchers said the gender imbalance problem cropped up in the late 1980s when the use of ultrasound technology became more prevalent.

研究人员认为性别不平衡的问题是在80年代后期，随着超声波技术的发展而产生的。

but four newcomers cropped up in the two years since then, and were innovative enough, or showed enough potential, to make it on our new compendium.

而另外四个新加入排行的扩展，全都是在近两年新近开发的，它们表现出了一定程度的创新性和充分的潜力。

an interesting question cropped up today: why isn’t apple in the dow jones industrial average?

今天，一个有意思的问题突然冒了出来：为什么道琼斯平均工业指数中没有苹果公司呢？

the tendency towards closer military alliance is on the rise. new forms of 「gunboat policy」 are rampant. regional conflicts have cropped up one after another .

强化军事同盟的倾向有所抬头，新的「炮舰政策」正在肆虐，地区性沖突此起彼伏。

but douthat says the same sort of phenomenon has cropped up in the realm of public policy with such endeavors as the wars in vietnam and iraq, or the european union「s creation of a common currency.

但杜塔特认为，同样的现象也出现在公共政策领域，比如越战和伊战，以及欧盟创造统一货币。

social problems cropped up in the wake of natural disasters.

自然灾害之后，出现了许多社会问题。

new difficulties cropped up [arose].

发生新的困难。

the frenchman rarely comments on the treatment he receives but thanked ferguson for his intervention when the issue cropped up at his pre-match press conference.

这位法国人从来不评介他受到的待遇，但是他感谢弗格森出手干涉这事。

the nickname for shantytowns that cropped up all over the country — hoovervilles— left little doubt as to who was blamed for the crisis.

国家出现了到处的棚屋城——胡佛没有留下谁应该承担责任的怀疑。

i had lots of fun but a few problems cropped up on my travels.

我玩得很开心，不过在旅途中也出现了一些突发问题。

problems on foreign language teachers have cropped up after the expansion of enrollment in local colleges and(universities).

扩招后的地方院校外语师资存在着一些突出的问题。

lecco」s walking bus was the first in italy, but hundreds have cropped up elsewhere in europe and, more recently, in north america to combat the trend.

莱科市的步行巴士在意大利尚属首例，但是在欧洲的其他地区出行了数百例，而且最近特别是在北美，有很多这样的例子，以阻止气候变暖的趋势。

the idea behind plam cropped up as part of a dce-replacement strategy.

plam背后的思想就是dce替换策略的一部分。

there appeared to have cropped up some difficulties in the management of the school.

在学校管理方面看来曾经出现过一些困难。

you seem to have cropped up badly on page 11, your acts are wrong.

看来你在第11页上出了严重错误，你所提供的情况不对。

at first all sorts of difficulties cropped up and delayed us. later we learnt how to anticipate these.

起初冒出来了各式各样的困难，耽搁了我们。后来我们学会了如何为这些困难预作準备。

the city council began looking into an ordinance regulating drug paraphernalia after it was discovered some tobacco shops that recently have cropped up in south beloit were selling these items.

市议会开始寻找到一个条例规范吸毒用具被发现后，一些烟草店，最近也出现在情报被卖这些项目。

a difficulty has cropped up at work.

工作中突然出现困难。

the shuttle's mechanical problem with its hydrogen venting system first cropped up in march during an initial attempt to launch space shuttle discovery.

航天飞机的这个有关其氢排气系统的机械问题，首次是在三月份在初次试图发射「发现号」航天飞机期间出现的。