韩国的国花、国树分别是（）。
A.郁金香、枫树
B.象牙红、梧桐
C.孔雀草、橡树
D.木槿花、松树
参考答案：D
欲设计C30普通混凝土（σ＝5），其试配强度为（）mpA．
A．21．8
B．38．2
C．30
D．40
The train was late and many people were kept _________ at the railway station.
to wait B. to be waiting C. waiting D. waited
