51.

1. devices
2. risks
3. phenomena
4. claims

52.

1. at least
2. at most
3. as if
4. as well

53.

1. blocking
2. cooking
3. exhausting
4. cooling

54.

1. Except
2. Even
3. Despite
4. Besides

55.

1. until
2. when
3. as
4. unless

56.

1. range
2. continue
3. spectrum
4. field

57.

1. Reasonably
2. Consequently
3. Amazingly
4. Undoubtedly

58.

1. identical
2. beneficial
3. preferable
4. susceptible

59.

1. effort
2. method
3. hunt
4. account

60.

1. do affect
2. did affect
3. is affecting
4. could have affected

(Reference keys.)