Deforestation is mainly caused by the cutting down of tropical forests to provide land for agriculture.

VOA: special.2010.04.06

Actually he gained power in Rome mainly by military might, by kind of making the Senate nervous and winning a few battles, and that was against the law.

事实上他在罗马提升势力，是由于强大军事实力，而且赢了几场硬仗战争，让元老院感到不安，这是违反法律的。

耶鲁公开课 - 新约课程节选

This means that all the area surrounding that Fairview Gardens was mainly farmland back in the 1950s, all growing food, probably a fair amount of it being eaten locally by people.

美景花园的整个周边地区,在上世纪50年代基本上都是耕地,都长着农作物,其中很大一部分被当地人消费掉

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

In nineteen eighty-three, the project was turned into an independent bank owned mainly by its borrowers.

VOA: special.2010.06.16

In many areas,villages were burned by Janjaweed militia, the government-backed, mainly Arab forces that pushed many Black African farmers from their land.

VOA: standard.2010.03.21

Most scientists believe the warming trend is mainly caused by human activity, especially the use of fossil fuels and the cutting down of forests.

VOA: standard.2009.12.09

The rebel group failed in its violent quest to establishment an ethnic homeland on the island, which is dominated by the mainly Buddhist Sinhalese.

VOA: standard.2009.11.09

The key populations as defined by the study are the people who are mainly drug injectors, men who have sex with men, and sex workers.

VOA: standard.2010.07.07

The killings were carried out mainly in small countryside villages predominantly settled by Roma.

VOA: standard.2009.08.22