It____ten years since I saw him last time.A has B was C had been D is

It____ten years since I saw him last time.A has B was C had been D is It____ten years since his father died .A is Bwas Chad been Dwill be 为什么选a请具体一些 1、It____ten years since he left Shanghai.A.were B.is C.had been D.will be2、She____sick for two days before Thursday.A.had been B.was C.has been D.is being 3、As a boy,James Watt,who invented the steam engine later,____questions.A.always asks B.h years This morning I went to the English corner which is in the park near my home.It is three years sinc SinA+SinB+SinC SinA+SinB+SinC 如何计算sinc函数 sinc interpolation是什么意思 为什么sinC=1? since+瞬间性动词的疑问It is two years since you come to see me.It is two years since you come here.since后面+的都是瞬间性动词,但第一句表示的是否定,两年没看了,第二句表示的是肯定来了两年了.请问这个sinc since 3 years ago.是时间点还是时间段3 years ago.是时间点还是时间段.2.since 1985 是时间点 还是时间段?3.It is +一段时间+ since从句.怎么翻译?自从.已经多少年了》?是这样翻译吗我在网上查的说，sinc matlab中sinc(t)和sinc(t.')有什么区别? 在△ABC中,tanAtanB=1,求sinC+sinC sinc函数的傅里叶变换是什么 在△ABC中,已知sinC+cosC=1-sinC/2,则sinC= 已知sinC+cosC=1-sinC/2求sinC的值 I have been riding the bike since I was ten years old.如何翻译since 后同样是be 动词表状态，第一句需要翻译为自从我病愈后他就再也没有来看过我。时间从表状态这个动作结束后开始算起。那第二句sinc