【题目】Magic shows are entertaining ______ the audience does not discover how the tricks are done.
A.so that
B.as long as
C.as if
D.ever since

【答案】B
【解析】句意：只要观众没有发现魔术表演是怎么做的，魔术表演就很有娱乐性。A. so that“以便”；B. as long as“只要”；C. as if“似乎”；D. ever since“从那时起",此处表示条件，故选B。