I greeted the teacher with “ hello” and the teacher gave me a sweet smile .A. by turnsB.

问题补充：

I greeted the teacher with “ hello”, and the teacher gave me a sweet smile .

A. by turns

B. in return

C. in turn

D. for turn

答案：

A. by turns

(答案→)B. in return

C. in turn

D. for turn

解析：考查turn的介词短语辨析。A/C依次，轮流；B作为回报，常常与for连用；D项不是固定词组。句意:我和老师打招呼“hello”;老师也给了我一个甜甜的微笑作为回报。根据句意说明B正确。