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刷刷题刷刷变学霸
举一反三
【单选题】It seems hard to watch someone yawn and not to yawn ourselves. Even reading about yawning can make you do it. Now, a new study has found why yawning has such a powerful force. Yawning when others yawn...
A.
It is natural to yawn back if people around you yawn.
B.
Some kids are too young to yawn after others.
C.
Yawning can be used to test children’s development.
D.
Kids with autism yawn easily when others yawn.