Table: t_1998_british_grand_prix
Columns: driver
constructor
laps
time_retired
grid

Question: What is the average number of laps for mika salo's arrows car with a grid over 13?
SQL: SELECT AVG("laps") FROM t_1998_british_grand_prix WHERE "constructor" = 'arrows' AND "driver" = 'mika salo' AND "grid" > 13

Question: Who drove the car with a grid of 7?
SQL: SELECT "driver" FROM t_1998_british_grand_prix WHERE "grid" = 7