the population of the united states is about 295 million,that of china ,

问题描述:

the population of the united states is about 295 million,that of china ,
the population of the united states is about 295 million,_____ that of china ,almost the same size as america,is 1.3 billion.
a.as b.when c.while d.since

C while 而,然而,隐含前后两者有比较之意.