A:CO(NH2)2、NH4CNO
B:白磷、红磷
C:12 H、 13 H
D:CH3CH2CH2CH3、
A: Can I help you?
B: Yes. The green scarf is very pretty. How much is it?
A: It's $100.
B: It's too expensive. What about the sunglasses?
A: They're $20.
B: They're cheap. I like them.
2个苹果,平均分给5个小朋友,每个小朋友分到多少个,还剩多少个。
22÷5=____(个)……____(个)
等差数列an的前n项和为Sn,a5=11,S12=186,则a8的值( )