Find a mistake in each sentence and correct them

IV/ Find a mistake in each sentence and correct them:
71. We don’t want buy any writing pads. ____________
72. The magazines on this rack is in English. ____________
73. After the first two lessons we have a twenty- minutes break. ____________
74. After our vacation in Ha Long Bay we returned to home by bus. ____________
75. We are happy hearing that you’ve passed the final exams. ____________
76. How many times in a day do you brush your teeth? ____________
77. The dirt on vegetables can cause you sick. ____________
78. She bought some souvernirs from the shop and so was I. ____________
79. Scientists say that the life started in the ocean. ____________
80 10. Indonesia is one of the strongest country in badminton. ____________