四、隨一國對進口品課徵關稅而產生的收入效果(revenueeffect)與保護效果 (protectiveeffect)所指為何?而關稅課徵的方式包括:從價關稅(ad valoremtariff)、從量關稅(specifictariff)與複合關稅(compoundtariff) 等,有關這些關稅課徵方式的內容為何?(25分)