Williamhascuthissmoking_____tofivecigarettesaday.
A
cut down “削减，减少 ”;cut sth. down to “ 把⋯⋯ 减到(什么程度) ”，是固定搭配，而且符合题意。
It seems as if the sun_____round the earth since it rises in the east and sets in the west.
Icanspeak_____German.
Ifhe_____thestorekeeper‘sscissors，hewouldhaveforgottentobuyapair.
Those people_____a general understanding of the present situation.
Thosepeople_____ageneralunderstandingofthepresentsituation.