Work has begun to determine the feasibility of using insects as biological controls, but effective biological controls are considered years away.

人们已经开始努力确定使用昆虫作为生物控制手段的可行性，但仍认为有效的生物控制手段还需要数年时间。

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Food companies have been trying to make effective satiety-inducing foods for years, but with little success.

食品公司研发能够有效诱导饱腹感的食物已经有数年了，但没有任何进展。

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"We've been working on this problem for over 10 years and the vaccines we've tried in the past have induced some immune responses but they have not been very effective."

我们已经研究这个问题超过10年了，之前的一些疫苗能够引发一定的免疫反应，但是并不足够有效。

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Over the last 15 years this simple but effective improvement resulted in entries as early as October 16 and as late as November 28, and exits as early as April 20 and as late as May 16, and with performance that substantially beat not only the market but the impressive Sell in May strategy.

FORBES: Sell In May Could Still Come Into Play But Don't Bail Now

Police and Crime Commissioner Christopher Salmon said the 3.9% rise was smaller than in recent years but would pay for "effective policing" on minimal cost.

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But in recent years, they have been less effective at developing the same level of grass-roots energy as earlier movements, including their own in the 1970s.

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