单项选择题
A．they were too soft to bear the climber's weight B．they were the only pitons he could afford to buy C．they coul not last long D．they were made of iron
A．a discount for becoming members B．a box which fits nearly into most car C．a selection of parts which may be needed D．a chance to rent a car cheaply
A．driving short distances in hot weather B．having their car insured for ￡ 20 C．driving slowly at all times D．making sure their car is in good working order