请根据所给首字母或中文提示，在横线上写出单词在句中的正确形式。

71. Mr. Smith lives on the ______(第六) floor.

72. He ______(付款) about three thousand yuan for his iPhone 4 yesterday

73. Lisa learns to play the piano on every ______(星期二)

74.Walking on the beach makes you feel ______(放松的)

75. There is a science lab ______(在…后面) the library.

76. --- It’s a bit hot here. Could I o_____ the window? ---- Of course.

77. There’s no bridge over the r_____. We have to cross it by boat.

78. The Chinese people are p______ of the Great Wall.

79.Fish can’t live w______ water.

80.Please help y______ to some fruit, Lisa!