86．When did you join us ____ the game?　

85．What ____ earth can you see?

84．Hundreds ____ years ago, there was a village here.

83．Are you interested ____ the film Titanic?

82．We can finish the work ____ a week.

81．I feel ____ going for a walk.

80．Please cut the metal ____ some pieces.

79．____ Mr Wang's help, I have passed the exam.

78．Nothing can stop us ____ studying hard.

77．Tie the horse ____ the tree.