—What colour __________your shoes?— __________ black.
A:is; It's
B:is; Its
C:are; Their
D:are; They're
以点电荷为球心的球面上各点的电场强度和电势处处相同.____ (判断对错)
澳门建立特别行政区之前曾被哪个国家侵占达400多年?( )
传说中的炎帝和黄帝是中华民族的人文始祖。下列有关黄帝的叙述不正确的是( )