puzzeled
春芽
共回答了25个问题采纳率:92% 举报
It is a good manner to say "Thank you." when you get something from others.
'It' 形式主语,真正的主语是 to say " Thank you." 系动词是 is,单数形式,所以用 a good manner.
还原:To say " Thank you." is a good manner when you get something from others.
1年前
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