二尖瓣狭窄时何情况下发生栓塞
A．左心衰时
B．房颤时
C．右心衰时
D．心内膜炎时
E．褥疮时
参考答案：B
—You look unhappy, what's wrong?
—I _______ with my brother. [ ]
A. argued
B. helped
C. played
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