"is give" or "is to give"

[frogprince]

When meteorologists detect a tropic cyclone, the first thing they do is give a name to it.

The words, is and give, are verbs. Is it okay to put two verbs together? Any grammar rule?
What if I write this sentence in this way: ..., the first thing to do is to give a name to it?

 

[. 1]

I am not sure that 'is' could be called a verb.
It sounds like a conjunction.

The construction seems fine but the descriptive is tropical not tropic.

.,,

 

[la gitana]

Is exists as a form of the verb to be; therefore, you must use the infinitive after the conjugated verb: Is to give.

 

[Dimcl]

When meteorologists detect a tropic cyclone, the first thing they do is give a name to it.

The words, is and give, are verbs. Is it okay to put two verbs together? Any grammar rule?
What if I write this sentence in this way: ..., the first thing to do is to give a name to it?

I think that the sentence would more usually be phrased this way:

"When meteorologits detect a tropical cyclone, the first thing they do is give it a name"