After completing and signing it, please return the form to us in the envelope .A. providin

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A. providing
(答案→)B. provided
C. having provided
D. provide
解析：考查非谓语动词的用法。此处动词provide与其逻辑主语envelope之间是被动关系，在句中作定语，相当于which is provided。句意为：完成并签名后，请把表格放入我们提供的信封内送回。