Help me study for my Economics class. I’m stuck and don’t understand.

The graph above shows the demand and supply of wrenches for the country of Spain.

• If trade is avoided, Spain consumes _____ wrenches at a price of _____ per wrench.
• With free trade, for a world price of $4 per wrench, Spain is producing _____wrenches.
• With free trade, for a world price of $4 per wrench, Spain is consuming _______ wrenches.
• With free trade, for a world price of $4 per wrench, Spain is importing _________wrenches.
• If the world price is $4 per wrench, and the government of Spain imposes a tariff of $2, Spain produces ____________ and imports __________wrenches.
• If the world price is $4 per wrench, and the government of Spain imposes a tariff of $2, how much tariff revenue will the Spain’s government collect?_____