Tìm lỗi sai và sửa
81. A. has supplied -> has been supplying
82. A. have been -> was
83. B. informations -> information
84. A. were -> are
85. A. have never been understand -> have never understood
86. B .has ever applied -> has ever been applied
87. C. has been deciding -> has decided
88. D. but -> bỏ but
89. A. have started -> started
90. D. on next Friday -> next Friday