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题库 / Prep2007E2-SC-144
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.
grains of sand or of pebbles, burn up speeding
grains of sand or pebbles, burn up while speeding
grains of sand or pebbles, which burn up while speeding
a grain of sand or pebble, which burns up as it speeds
a grain of sand or a pebble, burns up when it speeds
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often no larger than grains of sand or of pebbles是插入语，when后面从句，主语是tiny flecks，排除CDE
语意为在speeding的过程中burn up，故B正确
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