— I wonder what Mr. Wang asked you just now?
— He asked ________ .
A:whether I will take part in the singing competition
B:how long I have bought my new bike
C:what was wrong with my old bike
D:how much money did I spent on books
读“中国及周边地区略图”,分析回答问题。
“蒸汽时代”和“电气时代”是人类工业文明进程中的里程碑,它们都( )