检测压力机的几何精度需要哪些工具检测？
参考答案：
检测几何精度的常用工具包括：
平尺、磁力百分表、直角尺、塞尺。
Canada has almost ________ as China, but it doesn't have ________ as that of China. [ ]
A. the same size; so a large population
B. the same size; so large a population
C. as; as a large population
D. so large; as large population
食管癌的晚期症状有
A．吞咽困难
B．声音嘶哑
C．呕吐
D．锁骨上淋巴结肿大
E．胸背疼痛
