They were filled with joy when they Chinese soil in late July.A. set foot inB. set foots i

问题补充：

They were filled with joy when they Chinese soil in late July.

A. set foot in

B. set foots in

C. set foot on

D. set foots on

答案：

A. set foot in

B. set foots in

(答案→)C. set foot on

D. set foots on

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