今天我们将学习使用动词不定式表示原因。请学习以下例句：I am going to Beijing to work.（我将去北京工作）Why are you going to Beijing?（你为什么要去北京）I am going to Beijing to work.（我将去北京工作）Why do you take a passport to travel?（你为什么带着护照去旅行）I take a passport to travel because it’s necessary to leave the country.（我带护照因为离开国家时需要）I check the weather forecast to see what kind of clothes I need to take with me.（我检查天气预报看看我需要带怎样的衣服）Whenever I arrive in the US, I will rent a car to go to Miami.（当我抵达美国，我将租车去迈阿密）这些句型中“to do something”所构成的动词不定式都表达出了原因。现在请试着回答以下问题：Why do you take toothpaste when you travel?（你旅行时为什么带着牙膏）Why do you take sunscreen when you travel?（你旅行时为什么带着防晒霜）Why do you rent a car?（你为什么要租车）Why do you book a flight?（你为什么预定机票）Why do you study English?（你为什么学习英语）