Amanescapedfromtheprisonlastnight.Itwasalongtime_____theguardsdiscoveredthat.A.whenB.untilC.sinceD.before
题目
Amanescapedfromtheprisonlastnight.Itwasalongtime_____theguardsdiscoveredthat.
A.when
B.until
C.since
D.before
A.when
B.until
C.since
D.before