PREP 115

daodaodog

Meteor showers and individual streaks of light that flash across the sky every night are generated when tiny flecks of celestial 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

C. grains of sand or pebbles, which burn up while speeding

D. a grain of sand or pebble, which burns up as it speeds

E. a grain of sand or a pebble, burns up when it speeds

问一个细节，tiny flecks of celestial detritus, often no larger than grains of sand or pebbles,

这里often no larger than。。。是修饰flecks还是detritus的？

另一个例子：at the foot of the highlands, which was a source of jade...

这里的which是修饰foot的（从语法上）？

daodaodog

求助啊~