按照公债本位对公债进行分类,可以将公债划分为()。
A.有期公债和尤期公债
B.国内公债和国外公债
C.强制公债和自由公债
D.货币公债和实物公债
参考答案:D
A: You look very nice in your new dress today.
B: Oh, really? I _________ it when it was on sale. [ ]
A. buy
B. bought
C. have bought
D. will buy
马的体细胞中有32对染色体,精子中有______条染色体,卵细胞中有______条染色体,受精卵中有______条染色体.