问题补充：
Mr. Li will go to Guangzhou by air. His workmates are at the airport.
A. turning him off
B. seeing him off
C. taking him off
D. putting him off
答案：
A. turning him off
(答案→)B. seeing him off
C. taking him off
D. putting him off
解析：句意:李老师将坐飞机去广州，他的同事们将去机场送他。根据句意可知李老师去广州这件事情是将来的，因为will go to ，故同事们去机场送行也应该是将来的。此句用现在进行时来表示将来。turn off 关掉；see sb. off 为某人送行；take off 飞机起飞；脱掉；put off 推迟。故选B。
