Once , it can never be forgotten.A. seeB. to be seenC. seenD. saw

发布时间：2020-08-15 01:53:18

Once     , it can never be forgotten.
A. see
B. to be seen
C. seen
D. saw

网友回答

A. see
B. to be seen
(答案→)C. seen
D. saw
解析：seen是过去分词,它用作时间状语时,常与once, when, whenever, while,until一起用.
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