A．what

B．who

C．whose

D．where

阅读短文，把A-D四个选项填入文中空缺处(1—4)，使短文完整正确，并完成第5题。
     A lot of people keep asking, "How do I improve my English?" There are many possible answers, but
    here are just a few pieces of advice.
 1. _______________________________________________
     Sure you have teachers, reading materials, and websites to help you with your English, but who is
    really responsible for making sure that you learn English well? Nobody but you.
 2. ______________________________________________    
     If you are interested in English, remember that it is all around you. You can do many things that will
     help you learn English. Find things to do where you need to use English.
     Listen to the radio in English. Watch TV and movies in English. You can also speak in English with
     your friends. Get a language partner and speak in English as much as possible. Finding friends whose
    native language is English is even better.
     Other ideas: Take an English class, join an English group, find a tutor, and read English magazines.
     Do whatever you can to keep using the language.
3. ________________________________________________   
    This means that you should pay attention to how you use English. Think (a little) about how you are
    going to say something before it comes out of your mouth. But don't think about all of the problems you
    have in English at the same time. Just choose something that you know you are having difficulty with and
    work on using it correctly. 4. _______________________________________________