Until recently, the Inuit people led a nomadic existence, sheltering in
igloos, the ice-block domes that are peculiar to north-central LACE w:st="on">CanadaLACE>,
and in structures made of stones, bones, driftwood, and skins.
A. Until recently, the Inuit people led a nomadic existence, sheltering
B. During recent times, the Inuit people lead a nomadic existence, sheltering.
C. In the times that are recent, the Inuit people led a nomadic existence, sheltered.
D. Up until recently, the Inuit people, leading a nomadic existence, have sheltered.
E. Until recent times, leading a nomadic existence, the Inuit people were sheltered.
做题的时候选了A，答案是D
但是D第一：up until recently不知道是什么用法，第二，分词放在了主谓之间，不是有名的夹心修饰歧异么？ | 
d就避免了这个问题,并且完成时态也不叫合适
