During the scientific experiment, Mr. Chen carefully poured the water into the tube, with my classmates beside to see what would happen.
A. were standing
B. stood
C. standing
D. to stand
网友回答
A. were standing
B. stood
(答案→)C. standing
D. to stand
解析：介词with+宾语+宾语补足语形成的介词短语。在句中作状语，表示伴随的情况。