我的prep模考里的两个sc，请大家帮忙，我后天下午就考试了，有点急

The electronics company has unveiled what it claims to be the world's smallest network digital camcorder,the length of which is that of a handheld computer, and it weighs less than 11 ounces.

is the world's smallest network digital camcorder, which is as long as a handheld computer and weighs---正解

这样的话不是两个谓语动词了,一个has unveiled还有一个is,因为 what从句里面的动词应该是claims吧...

Meteor showers and individual streaks of light that flash across the sky every night are generated when tiny flecks of celetial detritus, often no larger than grains of sand or of pebbles, burn up speeding through the atmosphere.

A.grains of sand or of pebbles, burn up speeding
B.grains of sand or pebbles, burn up while speeding---正解
这两项不知道有什么必然的区别,尤其是前面的部分,我当时想介词应该是尽量补出的,所以一冲动就选了A...
另外,后面的部分while这种连词不是不应该随便加进去,是不是说while+-ing动词的逻辑主语是句子主语那就是说tiny flecks speed through the atmosphere...是什么意思???(⊙_⊙)？
ps:其他的几项都是必错的主谓一致和句子完整性的问题

第一个可以理解为 what is it claims

我觉得我好弱呀...我现在可能开始钻牛角尖了，听不懂你说的呢...what is it claims... 哦，意思是说what引导的是unveiled的宾语从句吗？what能引导宾从吗？unveiled （that） what it claims is...是宾语从句里面的小主语从句吧..这种情况下就不用that了？

我真的很钻牛角尖...原谅我吧...

期待进一步解答

hello，

有人吗？

MM,第一题我是这样想的- 将what it claims...成分看成what引导的名词性从句（what it claims本身就相当于一个名词成分），类似的还有What you said made me crazy.这里made就是动词，所以这样的结构是允许的，如果实在不行就记住这样的结构吧。unveiled后面可以跟is，例句：the Russian government unveiled what it said were previously classified documents showing prewar Polish cooperation with Nazi Germany.（NY times里的，一般不会错）

第二题我觉得speeding是burn up的伴随成分: when tiny flecks of celetial detritus, often no larger than grains of sand or of pebbles(插入语）, burn up while (they=tiny flecks of celetial detritus) speeding through the atmosphere.

不知道这样讲是否可以有点帮助...