The children entered the dining room, smiling and ______, and ______ down to have lunch.
No one has yet succeeded in solving the _____ of how life first began.
_______ his sister, Jack is quiet, and does not easily make friends.
. The television station reported several times to _________ drivers parking their cars on the blind road.
——Can I smoke here? ——Sorry. We don’t allow _______here.
Can you tell me ______?