Given:

To find:
The additional pair of corresponding parts that needs to be congruent in order to prove that
by ASA.
Solution:
According to ASA, two triangles are congruent if their two corresponding angles are congruent and their included sides of those angles are also congruent.
In
,
[Given]
[Given]
Clearly, SP is between angle S and angle P, and MO is between angle M and angle O.
Then,
as
by ASA.
Therefore, the additional pair of corresponding parts that needs to be congruent in order to prove that
by ASA is
.