51. In some remote places there are still very poor people who can’t afford to live in __conditions.
A) gracious B) decent C)honorable D)positive

52. Since our knowledge is __ none of us can exclude the possibility of being wrong.
A) controlled B )restrained C)finite D)delicate

53. You shouldn’t __your father’s instructions. Anyway he is an experienced teacher.
A) deduce B) deliberate C)defy　 D)denounce

54. The company management attempted to __information that was not favorable to them, but it was all in vain.
A) suppress B) supplement C)concentrate D)Plug

55. It is my hope that everyone in this class should __ their errors before it is too late.
A) refute B) exclude C)expel D)rectify