71.  He though that it was taken by me and he told to the other friends about it.

72.  They will go to London from Beijing by bicycle.

73.  Tom was praised by the firefighters' leader.

74.  When I t some difficult problems, I would ask my classmate by hone.

75.  We will have tests in five subjects by the end of this term.

76.  Dear manager, I want very much to be accepted by your company.

77.  A new computer has been bought by the CAAC.

78.  Travellers have been greatly helped by the new computer.

79.  A new computer has been bought by the CAAC.

80.  Travellers have been greatly helped by the new computer.