76．Choose my subject．Something about English, ____ example.

75．He watched me ____ surprise.

74．Ships can travel ____ the world.

73．The knife is made ____ metal and wood.

72．We are twins．People often mistake us ____ each other.

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

70．I saw him ____ the crowd.

69．The glass is full ____ milk.

68．The doctor operated ____ my mother at once.

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