我国华北地区晚奥陶世上升为陆地，直到中石炭世或晚石炭世才再次沉降海侵，到二叠纪就又全部隆起成陆，直到今天。
参考答案：对
—Would you tell me ____you want your tea, with sugar or milk?
—Sugar, please.
A．whether
B．when
C．what
D．how
I didn't know _____ yesterday.[ ]
A. why isn't Danny in school
B. why wasn't Danny in school
C. why Danny isn't in school
D. why Danny wasn't in school
