病毒的遗传物质是
A:DNA
B:RNA
C:主要是DNA
D:DNA或RNA
我国人口的突出特点是( )
We want students for the school show. If you _________ play the guitar, please talk to Mr. Zhang after school.
(Ⅰ)求数列{an},{bn}的通项公式
(Ⅱ)证明:数列{bn}中的任意三项不可能成等差数列.
关于日本的叙述,正确的是( )