心房舒张时，防止血液逆流的结构是
A. 肺动脉瓣、二尖瓣
B. 主动脉瓣、三尖瓣
C. 主动脉瓣、肺动脉瓣
D. 二尖瓣、三尖瓣
E. 肺动脉瓣、三尖瓣
Emma seldom allowed my mother to go to parties.
A. 对
B. 错
My mother was confined to her room for an entire year.
A. 对
B. 错
Passage 1
A. When I reached L.Rarick, she was______. a. very suspicious b. greatly surprised c. embarrassed d. unhappy
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