Table: avalon_2
Columns: ship_s_name
entered_service
ended_service
gross_tonnage
type_of_vessel

Question: Tell me the average gross tonnage for april 1919 entered service
SQL: SELECT AVG("gross_tonnage") FROM avalon_2 WHERE "entered_service" = 'april 1919'

Question: I want the total number of gross tonnage when entered service was 1903
SQL: SELECT COUNT("gross_tonnage") FROM avalon_2 WHERE "entered_service" = '1903'