单选题 根据以下听力内容,完成短文填空. <iframe src="/module/audioplay.html?objectid=c3d803d8bd633358434a5f6097a1d0b5"></irame>When I need gas for my car, I pull into a gas station right around the comer from my house and use my gas card. Years ago, full-service gas stations were very 1___________. However, things have changed. Now, most gas stations are self-service centers. Personally, I 2___________fill the car up with gas every time I stop. I generally 3___________, but more and more gas stations accept credit cards. As gas prices are 4___________, I'm now thinking about buying a more fuel-efficient vehicle or just 5 ___________ to work.