根据对话情景选择恰当的选项。

A: Meimei! It's time to get up, or you'll be late!

B: Don't worry, Mom. ____

A: How? With so little time!

B: You know, sometimes ____

A: But a good breakfast is very important, so you should have breakfast on time.

B: Mom, last night I had so much homework to do that ____

A: I see. ____ But it doesn't take you much time to have breakfast.

B: OK, Mom. I'm coming.

A: Meimei, having breakfast on time can help you to work better and play more happily. ____

B: I know, Mom. Thank you. It's time to go. Bye-bye.

A: Bye.

右图是北美洲伊斯帕尼奥拉岛（即海地岛）1493—1570年人口变化图，导致这一变化 的主要因素是(　　)

①殖民者残酷的奴役剥削

②大批土著被贩卖到欧洲

③传染疾病的肆虐

④工业生产污染严重

据资料统计：在明后期至清前期200余年间，世界白银产量的一半流入中国，拥有一流城市、最为密集和完善市场网络的中国，成为当时世界经济和贸易的中心区域。然而当时它却没有形成强大的扫荡旧经济基础的革命性变化。其内在的原因在于

下表为某电烤箱铭牌，如图虚线框内所示是其内部简化电路图，Ｒ₁和Ｒ₂均为电热丝。