Final answer:
The sentence 'We'll start our race slowly and then go quickly' contains two adverbs: 'slowly' and 'quickly' which modify the verbs 'start' and 'go' respectively.
Step-by-step explanation:
The two adverbs in the sentence "We'll start our race slowly and then go quickly" are slowly and quickly. An adverb is a word that modifies a verb, an adjective, or another adverb by providing additional information about how, when, where, or to what extent the action is carried out.
In this sentence, 'slowly' modifies the verb 'start' by describing the manner of starting, and 'quickly' modifies the verb 'go' indicating the manner in which the race will proceed after starting.