板式塔的益流方式有（）。
A.U形流
B.单益流
C.双益流
D.阶梯式流
参考答案：A, B, C, D
—How is it going, Julie?
— _____.[ ]
A. It is well done
B. Thank you for your asking
C. It's a fine day
D. Pretty good
种皮最外层为1列径向延长的石细胞，呈栅栏状
A．木瓜 B．五味子 C．山楂 D．补骨脂 E．枳壳
