85．There are a group of sheep ____ the foot of the hill.

84．I saw him ____ the crowd.

83．The glass is full ____ milk.

82．The doctor operated ____ my mother at once.

81．My mother is ill．I have to send ____ the doctor.

80．Are you ____ trouble, Jim?

79．The students walked ____ the gates with Uncle Wang.

78．What have you done ____ the milk?

77．I'm sorry．I won't talk to others in class ____ now on.

76．If you break the window, you'll have to pay ____ it.