Finally, we back to the PRESENT!

First, just make a note that to talk about a surprise, use the noun la sorpresa and the verb sorprender.

Now, Progressive Tenses of Verbs:

Remember that you form the present progressive by using the present tense of estar + -ando, -iendo/-yendo forms.

To make these forms, drop the ending of the infinitive and add -ando or -iendo/-yendo.

hablar becomes hablando
comer becomes comiendo
escribir becomes escribiendo
leer becomes leyendo

When verbs have to vowels right before the end, like leer, creer, and oír, change the i to a y in -iendo.

When the stem of an -er or -ir verb ends in a vowel, there is a spelling change in the ending.
Also, remember that some -ir stem-changing verbs have a stem vowel change.

pedir --- pidiendo
dormir --- durmiendo


The progressive can also be used to talk about a past action. To form the past progressive, use:
the imperfect tense of estar + -ando, - iendo/-yendo forms.

The only time that you use the progressive tense is when an action is actually going on, or was actually going on at the time. Think of it as an -ing verb in english.

Present:
Isabel está hablando con don Miguel.
Isabel is talking with Don Miguel.

Past Progressive
Isabel estaba escribiendo un artículo sobre el temblor.
Isabel was writing an article about the earthquake.