________，he had no time to rest.
C
译文：尽管他很累，他也没有时间休息。此题考查的是让步状语从句，从句中表语提前。
The outline of rooftops and chimneys ________ against the pale sky.
Robots differ from automatic machines ________ after completion of one specific task，they can be reprogrammed by a computer to do another one.
It has been found that a strong ________ help overcome the effects of distraction.