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單項選擇題

I have spent a lot of time（）working on this problem.

A.at
B.–（不填）
C.on
D.with

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單項選擇題

She likes to spend time（）with her grandchildren.

A.play
B.to play
C.playing
D.played

單項選擇題

China is（）the east of Asia.

A.in
B.to
C.on
D.at