单项选择题 What does tax exhaustion mean? A、All avenues have been explored to minimise corporation tax. B、As deductions have reduced tax payable to zero, further deductions won't save tax. C、Non-current assets have a zero tax written down value. D、Tax liabilities have been completely discharged

单项选择题 3.被称为大自然的模仿大师，擅长模仿植物的叶片。 A. 蜻蜓 B. 螽斯 C. 菜粉蝶 D. 蝗虫

问答题 简述机器人弧焊熔化极气体保护焊和非熔化极气体保护焊的不同。