_____you understand this rule ，you‘ll have no difficulty in dealing with such problems.
D
once意思是“一旦”。while“當(dāng)??時(shí)候”;though“雖然”;unless“除非”。“一旦你明白了這個(gè)規(guī)則，處理類似的問(wèn)題就不困難了。”顯然，d符合句子意思的表達(dá)需要。
Iwilldotheclearingifyousee_____thelunch.
_____alltherepresentativesstillnotthere，themeetingwaspostponedforseveralhours.
Theteachergave_____theexaminationpaper.
Hedrovefastandarrivedanhour_____ofschedule.
Hisarticleisbetterthan_____intheclass.
