Britishpeoplesay"please"and"thankyou"allthetime_______somepeopleinAsiamaythinkitunnecessary．（）A.whileB.whenC.untilD.since

　　British people say"please"and"thank you"all the time _______some people in Asia may think it unnecessary．（）

　　A.while

　　B.when

　　C.until

　　D.since