纵隔肿瘤的临床表现有（）
A.咳嗽，呼吸困难，发绀
B.吞咽困难
C.肋间神经痛
D.Horner综合征
E.上肢疼痛麻木
参考答案：A, B, C, D
-- I was wondering if we could go hiking on the weekend?
---_______good.
A．Sounds
B．Sounded
C．Sounding
D．Sound
禾谷类作物和油菜的花粉粒发育至二核阶段时，花粉囊便开裂散粉。
