Questions 17-20 are based on comments on job interviews. You now have 20 seconds to read Questions 17-20. How long does an interview usually last according to the speaker

A．When large amounts of rock, mud and other loose materials are suddenly uprooted and sent sliding down a slope.
B．This might be caused by an earthquake or it might happen after a heavy rain or when soil becomes waterlogged after a fall of snow.
C．This might be caused by forest fire.
D．The hillsides have been stripped of trees which are rooted on them.

A．Tom.
B．Tim and Mary.
C．Mary and Tom.
D．Tom, Mary and Tim.