--- Could you tell me why I am constantly yawning this afternoon? ---Yawning ______ an indication that your body lacks oxygen and needs a rest.
Mr.Smith was much surprised to find the watch he had had__________was nowhere to be seen.
__________along the quiet road at forty miles an hour,and then an old man suddenly started to cross the road in front of me.
The policeman came up to the lonely house with the door __________,__________there for a while and then entered it.
The boy often gives a satisfactory answer to the teacher’s question,__________ just a minute.So he’s usually the teacher’s pet.
A doctor can expect__________at any hour of the day or night.