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题目内容
（国家开放大学管理英语3）
Apple almost lost its dominance in the smartphone market ________ it became clear that it was difficult to make a call using the much expected iPhone 4.
选择一项：
A.
when
B.
that
C.
where
选择一项：
A.
when
B.
that
C.
where
参考答案