77. The party lasted all night.
-> How long ..........................................................?
78. She talked to him for an hour.
-> How long ...........................................................?
79. It takes me 30 minutes to go to school.
-> How long .............................................................?
80. It takes her 32 hours to go to Ha Noi by train.
-> How long ..............................................................?
81. I am reading an English book at the moment.
-> What ......................................................................?