A:工业用焦炭在高温下还原二氧化硅制得高纯硅
B:SiO2可用于制造光导纤维
C:钠是一种强还原剂,可以把钛、锆、铌等从其熔融盐中置换出来
D:氧化镁熔点高达250℃,是优质的耐高温材料
________Tom________ Mary speaks good Chinese, so they can talk with these Chinese students very well.
下列能构成生物圈的是( )
—I'm a little hungry, let's have lunch first.—Ok! Let's go to _______.