_______ for the free ticket, I would not have gone to see film so often.
A. If it is not
B. Were it not
C. Had it not been
D. If they were not
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金属的塑性和其柔软性的关系是()
A. 金属的塑性和其柔软性之间没有必然连系
B. 塑性提高柔软性增加
C. 塑性降低柔软性增加
目前,世界各国对去除钢铁表面的氧化铁皮采取了多种办法,我厂使用的是机械法()