某不纯的硝酸铵中氮的质量分数为36%,则此硝酸铵中混入杂质可能是[ ]
A.NH4HCO3
B.(NH4)2SO4
C.CO(NH2)2
D.NH4Cl
答案:C
The picture in an ad looks __ better than the real thing. [ ]
A. very
B.little
C.lots of
D.much
将一根长为374厘米的合金铝管截成若干根36厘米和24厘米两种型号的短管,加工损耗忽略不计,则最后剩余部分的管子最少是多少厘米
A.2 B.6 C.8 D.14