一般现在时： 问别人经常做的事情，为什么要做。
Why do you like truck?
Why do you learn English?
Why do you go to school?
Why do you cook food every day?
Why do you brush your teeth?
Why do you run every day?
Why do you play the piano?
Why do you want guitar?
Why trucks are so popular?
一般现在进行时：
问别人正在做的事情，为什么要做。
Why are you doing it now?
Why are you studying now?
Why are you brushing your teeth now?
Why are you writing now?
Why are you reading now?
Why are you playing piano now?
Why are you driving now?
Why having a truck is better?
一般过去时：
问别人已经做过的事情，为什么要做。
Why did you do it?
Why did you write this book?
Why did you make the table?
Why did you learn English?
Why did you cook the steak?
Why did you run away?
一般将来时：
问别人将要做的事情，为什么要做。
Why will you do it?
Why will you write the book?
Why will you make the table?
Why will you say that?
一般过去将来时：
问别人想要做的事情，为什么要做。
Why should we hire you?
