位于前纵隔的肿瘤有（）
A.胸腺瘤
B.皮样囊肿
C.畸胎瘤
D.神经纤维瘤
E.支气管囊肿
参考答案：A, B, C
Mother was worried because little Alice was ill, especially_______ Father was away in Canada.
A．as
B．that
C．during
D．if
丈量钻杆时用（）编号。
A.粉笔
B.广告色
C.白漆
D.红漆
