You____thatlettertoJames.However，youdidn't.
B
「句意」 你本应该给詹姆斯写信，然而，你没写。
「难点」 ought to have written 是虚拟语气，与本句句意相符。
Toobtainasatisfactoryresult，onemustapplytwo____ofpaintonacleansurface.
Itwasrecommendedthatpassengers_____smokeduringtheflight.
Evenifhisletter（）tomorrow，it（）toolatetodoanything.
Ineverregretted_____hisoffer,foritwasnotwheremyinterestlay.