药材横切面木质部有栓化细胞环的是
A．黄芩 B．丹参 C．柴胡 D．白术 E．苍术
参考答案：A
—What did you see when you came here?
—I found Jim _____ the desks. [ ]
A. clean
B. cleans
C. cleaned
D. cleaning
表明（）变化的化学方程式叫做热化学方程式
A、放热
B、吸热
C、热量
D、扩散
