After ten years abroad, he still recognized his old colleagues he set foot in China．
A. immediately
B. for the first time
C. while
D. moment
网友回答
(答案→)A. immediately
B. for the first time
C. while
D. moment
解析：从句式看这里需要连词，B是介词短语，D少the，A项immediately做连词，表示“一…就…”,while做连词，有虽然，当…时候，句意是：在国外呆了10年后，一踏上中国他就认出了老同事。选A。