评价单元的划分应以能够保证（）为原则。
参考答案：安全评价的顺利实施
The young man used to _____to work, but he is used to ______to work now.
A．drive, walking.
B．drove, walked.
C．drive, walks.
D．driving, walk
某人胃酸过多，他应该用下列哪种药品治疗 [ ]
A．阿司匹林
B．青霉素
C．麻黄碱
D．胃舒平
