英语选择题，求解释，谢谢。

1. Grass skiing is a rising form of entertainment,popular with young people,____ sliding on the grass could be adventurous and enjoyable.
A. who B. when C. where D. whose
答：D
译：滑草是一种新兴的娱乐形式，在年青人中很流行。他们在草地上的滑行即有惊险又好玩。
析：grass skiing 打错了。作为非限制性定语从句，应紧跟先行词。如为entertainment ,为什么不紧跟它呢？
Brazil is frequently pointed to as a nation with a major successful investment in energy coming from grains: it presently runs 330,000 automobiles on a water and alcohol mixture, replacing 10 percent of its previous oil supply.

2. Brazil is a nation with a successful investment in energy that comes from grains and _____ ten percent of its oil supply with grain energy is its current goal.
A. relaces B. has replaces C. replacing D. to be replaced

答：C
译：巴西在谷类能源的投资很成功。10%的然油供应用谷类能源是其当前目标。
析：原以为第二句话也有误。搜索网络找到类似句。原以为is 为as 之误。后来发现，还是作为并列句通顺。

3.The income gap in Switzerland is much smaller than in many other European countries______ the country's social stability and harmony.

A. ensuring B. ensured C. ensures D. to have ensured
答：A
译：瑞士的收入差距比其它欧洲国家的要小很多，确保了瑞士的社会稳定与和谐。
析：现在分词短语作状语表伴随情况。前面有无逗号均可。

1C 2C 3A
第一题people后面的句号改为逗号。
第二题题目没有错的，nation后面的with a successful investment in energy是形容nation的，而 that comes form grains是形容energy，提取主干其实就是Brazil is a nation. And 后面是可以独立为一句的。Replacing ten percent of its oil supply with grain energy 作为主语，is作为谓语，its current goal为宾语。
第三题countries后面可能漏了一个逗号，即前面所说的瑞士国家收入差距比欧洲很多其他国家小这一因素促使了后面的结果。

题目错漏百出！

1，Grass skilling is a rising form of enternment,popular with young people,where sliding on the grass could be adventurous and enjoyable.

2,Brazil is a nation with a successful investment in energy that comes from grains and replaces ten percent of its oil supply。

3，The income gap in Switzerland is much smaller than in many other European countries,ensuring the country's social stability and harmony.

答案是cca

答案分别是：c、C、A