53._________A.does B.doesn’t C.do D.don’t

Wouldn’t you rather your child _________________ t

已知波动方程为s=10sin（2πt－0．1x) m，则此波的波速为________；t=T／2时，波源的振动速度为________。

— Thank you for your delicious dinner.— ___________________.A、Don’t say that.B、I don’t t

Zhou Ming has few English magazines, ________？A、does heB、doesn’t heC、hasn’t he

There has not been a great response to the sale, ______？A．does thereB．hasn"t itC．hasn"t th

for（i=1，t=1，s=0；i<=n；i＋＋) {t=t*i；s=s＋t；}的时间复杂度为_________。