We find fast and comfortable to travel by plane.A. thatB. usC. itD. This

We find fast and comfortable to travel by plane.
A. that
B. us
C. it
D. This

A. thatB. us(答案→)C. itD. This解析：句意：我们发现坐飞机旅行是很快速也是很舒服的。It为形式宾语，后面的动词不定式做真正的宾语；fast and comfortable为形容词做宾补；故选C。

收益了

对的，就是这个意思

(答案→)Socializing keeps you slim/Keeping a busy social life makes people slim 解析：【小题1】根据文章第一段第一行Keeping a busy social life among lots of friends may keep people slimmer说明本文的话题就是Socializing keeps you slim。【小题2】本段讨论的正是social stimulation能让人减肥。【小题3】本文的话题是关于Socializing能让人减肥，告诉我们a busy social life的好处。【小题4】根据文章第二段第三行by converting white fat into brown说明是通过改变white fat的方法来减肥。【小题5】本句的翻译难点在于对这几个词“stimulate” “couch potato”的翻译过于死板，翻译不通。要根据上下文的语义来猜测这些词的意思。