Sure, I can help you complete these sentences using the first conditional form, which is used to express a condition that is possible and likely to happen in the future. The structure is usually "if + present simple, ... will + infinitive."
a. Ken will not go to Barcelona if he does not pass his exams.
- Here, the possibility of not going to Barcelona is dependent on not passing the exams.
b. If my friends come with us, we will have a really good time.
- This sentence suggests that having a good time is contingent on the friends coming along.
c. If Sonia falls down the mountain, she will not forget it!
- The sentence implies that falling down the mountain is an event Sonia will remember if it happens.
d. David will not go out this evening if he does not finish his homework.
- David's going out is conditional on whether he finishes his homework.
e. If the film starts at nine o'clock, we will have time to eat our dinner.
- This indicates that starting the film at nine allows enough time for dinner before it begins.
These sentences demonstrate how the first conditional can be used to talk about future events that are possible and likely, with their outcomes dependent on certain conditions being met.