David was born _____1994, and his birthday is _____ April 23rd.[ ]

A. in, on  

B. at, in  

C. on,on  

D. in, in

玩具电动机的设计特点是，要体积小、重量轻、耗电少、转矩大、工作电压高、工作电流小和便于生产时的组装。