You should give the book back to the library.(同义句) You should ---the book ---the library.

很高兴为你解答.
保证正确率~!
正确答案是：
You should give the book back to the library.
= You should 【 return】the book 【 to 】the library.
你应该把书还给图书馆.
【解析】：
give back ...to = return ...to 把...还给
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