Answer :
Answer: arrived
Explanation:
arrived would be a sensible answer to complete the sentence since buses are often associated with departure and arrival, therefore by missing it one would "arrive" late
We are late because we missed the bus. [present tense]
OR
We were late because we missed the bus. [past tense]
OR
We will be late because we missed the bus. [future tense]
OR
We were late because we missed the bus. [past tense]
OR
We will be late because we missed the bus. [future tense]