A:精子头部
B:雄原核
C:雌原核
D:受精卵
昨天是奶奶的生日,以An interesting birthday party为题…提示词:1. birthday , yesterday , morning2. go, the shop, buy , presents,3. go , see, presents , have a good time .4. go home until , nine o’clock , evening.An interesting birthday party
图示为我国某日某时刻天气形势图。读图,回答下列问题。
为了节能,许多奥运场馆采用LED发光二极管照明,二极管的主要材料是()