（1）     GWD-30-Q2

Caribou are wary animals with excellent hearing, so stalking them over the treeless landscape, getting close enough to kill it with nothing but a handheld lance, as Dorset people did, required exceptional hunting skill.

1. so stalking them over the treeless landscape, getting close enough to kill it
2. so to stalk them over the treeless landscape and get close enough to kill one
3. so in order to stalk them over the treeless landscape and get close enough to kill one
4. and so in order to stalk it over the treeless landscape, getting close enough to kill it
5. and so stalking them over the treeless landscape and getting close enough in order to kill it

B the best 

搞不懂为什么是 so to 呢

1. so stalking them over the treeless landscape, getting close enough to kill it
           
2. so to stalk them over the treeless landscape and get close enough to kill one
           
3. so in order to stalk them over the treeless landscape and get close enough to kill one
           
4. and so in order to stalk it over the treeless landscape, getting close enough to kill it
               
5. and so stalking them over the treeless landscape and getting close enough in order to kill it

A, D,E的it 均无指代对象

the only difference bwtween b and c is 'in order to' and 'to'

不定式表目的

to更简洁

分词不能做主语，而不定式可以，对吗？

in order to是连词不能做主语

粉刺可以做主语但是

1. so stalking them over the treeless landscape, getting close enough to kill it
           

用了逗号连接两个粉刺是不对的，应该用AND

排除法。Caribou are wary animals with excellent hearing

所以后面三个选项中ADE中出现it，则可以全部排除。

C明显不对

故选B

关于不定式做主语还不是很懂，求解。。。