51.

1. depositions
2. depictions
3. discussions
4. dispositions

52.

1. capable of
2. likely to
3. fit in
4. simply for

53.

1. must
2. need
3. may
4. can

54.

1. Neither ... nor
2. Either ... or
3. Both ... and
4. Not only ... but also

55.

1. program
2. software
3. parent
4. objective

56.

1. explicably
2. explicitly
3. explosively
4. expressively

57.

1. on
2. off
3. among
4. out

58.

1. since
2. if
3. while
4. although

59.

1. To some extent
2. By no means
3. In some aspects
4. For this reason

60.

1. setting out
2. setting up
3. setting off
4. setting aside

(Reference keys.)