Choose the sentence that has the same meaning as the first .

1) Stop talking or you won't  understand the lesson.

       A. If you don't stop talking , you won't understand the lesson.

       B. If you don't stop talking , you wouldn't understand the lesson.     

       C. If you hadn't stopped talking , you wouldn't understand the lesson.   

       D.If you hadn't stopped talking , you wouldn't have understand the lesson. 

2) You should clean this room every day .

        A.This room should be cleaned every day .

        B.This room should been cleaned every day .         

        C.This room should clean every day .    

        D.This room should be clean every day. 

3) My career as a teacher began 14 years ago

          A. I have started teaching for 14 years now.

          B. For 14 years have I been a teacher.

          C. I was a teacher for 14 years .

          D. I have been a teacher for 14 years now.

4) Ho Chi Minh City is the most crowded city is Vietnam.

           A. Ho Chi Minh City is not so crowded as all the other cities in Vietnam.

           B. Ho Chi Minh City is more crowded than all the other cities in Vietnam.

           C. All the other ciries in Vietnam are more crowded than Ho Chi Minh City.

           D. Ho Chi Minh City is as crowded as all the other cities in Vietnam.