某些化学试剂可用于净水,水处理过程中常用到一种无机高分子净水剂,它的化学式为[Al2(OH)nClm·yH2O]x式中m等于[ ]
A.3―n
B.6+n
C.6―n
D.3+n
答案:C
---Didn’t the neighbour see the man breaking into the house?
---No, she ______ in the other direction.
A.had looked
B.was looking
C.looked
D.is looking
一条直线比射线长10厘米.______.(判断对错)