题干
I enjoy learning English, it takes me a lot of time.
A：as if
B：though
C：because
D：for
答案(点此获取答案解析）
B
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＝1的两个焦点，点P在双曲线上，且满足∠F1PF2＝90°，则△F1PF2的面积是( )
