请问"第几节课"用英语怎么说?1.比如:第一节第二节第三节该怎么讲?2.世界时区里的"副二区分界"怎么翻译?请问到底是period还是class呀

the first/second/third class.

first/second/third period

1 the first class; the second class.
2 I'm not sure of it, suggest you find a map and later you will get the answer:)