—May I speak to Mr. Smith?
—Sorry, he _______ Australia. But he _______ in two days.
A:has been to; will come back
B:has gone to; will be back
C:has been in; would come back
D:is leaving for; doesn't come back
①保护党的先进性,巩固党的执政地位
②切实践行“三个代表”“科学发展观”重要思想
③贯彻实施依法治国基本方略,维护法律的尊严
④维护社会稳定,促进社会经济发展
如果某种生物的体细胞在细胞分裂前染色体数目为24条,那么在细胞分裂后和细胞生长后的染色体数目分别是 ( )
被称为“微生物学之父”的是( )
兔的体细胞有22对染色体,则兔的精子细胞中染色体是( )