呼吸机气囊内压应在（）.
A.<25mmHg
B.25～30mmHg
C.30～35mmHg
D.35～40mmHg
E.>40mmHg
参考答案：A
He arrived at the station, ______that the bus_____ off .
A．finding; had
B．found; had
C．only to find; had been
D．only to find; has been
对化疗较敏感的肿瘤（）
A.骨肉瘤
B.骨髓瘤
C.尤文肉瘤
D.恶性淋巴瘤
E.骨巨细胞瘤
