prep的2道语法题

1.Due to poaching and increased cultivation,there are fewer than 100 Arabian leopards left in the wild,reseachers have determined,making them many times more rare than 中国大熊猫。

Reseachers have determined that,because of poaching and increased cultivation,there are fewer than 100 Arabian leopards left in the wild,and that these leopards are thus many times more rare than...

请问原句错误在哪里，我觉得them并没有指代不清啊。。。后面那个是正确答案

2. More than 300 rivers drain into Siberia's lake Baikal,which holds 20 percent of world's fresh water,more than all the North America Great Lakes combined.

这句话哪里对了？

后面的那个more than 和前面的which holds...貌似都修饰主句的slb啊，可是感觉好怪。。。后面那个很poor啊，像fragment一样

囧

1.them虽然可以指代插入语，但是优先指代主句主语吧，而且正确选项有点复杂啊，用并列结构没有分词结构简洁。

2.后面的more than应该不是修饰drain的，drain 是动词

Prep1-24

Employment
costs rose 2.8 percent in the 12 months that ended in September, slightly less
than they did in the year that ended in the previous quarter.

(A) less
than they did

(B) less
than it did

(C) less
than they were

(D)
lower than

感觉了解一点了

不过那后面的slightly less than...难道不是修饰前面整句话的吗？不好意思，有点晚了。