种子中有生命力的部分是胚乳（）
A.正确
B.错误
C.不恰当
参考答案：B
关于急性左心衰的发病机制
阵发性室上性心动过速
A．左室充盈障碍B．左室后负荷突然增加C．左室舒张期过短D．左室排血量急剧下降E．左室前负荷突然增加
Although the teacher didn't mention any names, everybody knew who he was ________.[ ]
A．speaking to
B．turning to
C．referring to
D．talking to
