回答如下:
reciprocate 意思是:往复移动， 互给，互换，报答，酬答 。它既可作及物动词，又可作不及物动词。如:
In order to reciprocate the man 's kindness, she decided to give him a hand. (及物动词)
Look!The engine is reciprocating all the time. (不及物动词)
回答如下:
reciprocate 意思是:往复移动， 互给，互换，报答，酬答 。它既可作及物动词，又可作不及物动词。如:
In order to reciprocate the man 's kindness, she decided to give him a hand. (及物动词)
Look!The engine is reciprocating all the time. (不及物动词)