51.

1. diplomas
2. dilemmas
3. ailments
4. epidemics

52.

1. diminishes
2. deteriorates
3. ameliorates
4. relieves

53.

1. unaffected
2. unidentified
3. contaminated
4. undiagnosed

54.

1. distressed
2. attracted
3. distracted
4. frustrated

55.

1. asking
2. asked
3. having asked
4. having been asked

56.

1. Sadly
2. Happily
3. Consequently
4. Obviously

57.

1. determined
2. designated
3. doomed
4. satisfied

58.

1. neurotic
2. necrotic
3. neural
4. neutral

59.

1. Therefore
2. On the other hand
3. In turn
4. However

60.

1. reflect upon
2. stumble upon
3. bear upon
4. dwell upon

(Reference keys.)