- When is Lang Lang's concert?
- It's three o'clock the afternoon of December 18th.
A:at; in
B:at; on
C:on; in
D:in; on
用纯种的黄色圆粒豌豆与绿色皱粒豌豆杂交,F1全部是黄色圆粒,F1自交的F2,在F2中杂合的绿色圆粒有1000个,推测纯合的黄色皱粒有( )
鲫鱼、家鸽分别是鱼类和鸟类的代表动物,有关叙述错误的是( )
近地面大气的热量主要直接来自( )
给出下列三个类比结论:
①类比ax·ay=ax+y,则有ax÷ay=ax-y;
②类比loga(xy)=logax+logay,则有sin(α+β)=sinαsinβ;
③类比(a+b)2=a2+2ab+b2,则有(a+b)2=a2+2a·b+b2.
其中结论正确的个数是( )