原核生物、真核生物、病毒的遗传物质分别是:()
①DNA
②RNA
③DNA和RNA
④DNA或RNA
A.①②③
B.④④④
C.①③④
D.①①④
参考答案:D
She used ___with her parents, butnow she is used to ____ with her classmates at school. [ ]
A. live; liwing
B. 1ive; live
C. living; living
D. living; live
简述片麻状构造与片状构造的区别?