add to/add A to B

[joham]

Good friends ___ happiness and value to life. (add, add to)

The given answer is 'add to'. I'd think 'add' is the right answer. Am I right?

Could I ask native speakers to help me please? Thank you in advance.

[bhaisahab]

Good friends ___ happiness and value to life. (add, add to)

The given answer is 'add to'. I'd think 'add' is the right answer. Am I right?

Could I ask native speakers to help me please? Thank you in advance.

You are right 'add' is correct.