下列物质中原子是通过共价键结合的是( )
A.KF
B.NaCl
C.SiO2
D.MgO
答案:C
Anthropologist Barbara Myerhoff furthered her reputation as an authority on Native American culture with her study of the symbols, myths, and rituals of the Huichol people. ()
A. deserved
B. retained
C. renewed
D. advanced
“轻徭薄赋,与民休息”的政策实行于()。
A、三国时期
B、春秋时期
C、秦代时期
D、汉代时期