Với hàm số y=2tan(1-2x) thì đạo hàm bằng: 
A. -4xsin2(1-2x).
B. 4xsin2(1-2x).
C. -4sin2(1-2x).
D. -4sin(1-2x).

Choose the best answer for the following sentence:
They ______________________ by the sea.
A. are staying at a hotel                         
B. are staying a hotel
C. are being stayed a hotel                       
D. are being stayed at a hotel

Choose the best answer for the following sentence:
Peter is ______________________ John. 
A. younger and more intelligent than                             
B. more young and intelligent than                   
C. more intelligent and younger than                               
D. the more intelligent and younger than

Choose the best answer for the following sentence:
We watched the little girl _____________________ across the street.
A.  to walk               
B. walk                     
C. is walking                 
D. walked

Choose the best answer for the following sentence:
In conclusion, it seems that although there are big differences between countries, computers are ___________ than televisions in most countries.
A. much less common still
B. less common still much
C. still much less common
D. much less still common

Ảnh của (C): (x - 2)2 + (y+3)2=25 qua Tv→, v→=(-3; 4) là
A. (C'): (x + 2)2 + (y-3)2=25
B. (C'): (x - 2)2 + (y+3)2=5
C. (C'): (x - 1)2 + (y + 1)2=25
D.  (C'): (x + 1)2 + (y - 1)2=25

Choose the best answer for the following sentence:
Every time I miss the bus, it means that I ____________ walk to work. 
A. has to 
B. had to  
C. have to  
D. could

Choose the best answer for the following sentence:
Please don't mind. It's my ____________ to help you whenever you want. 
A. pleasure                      
B. pleasant                  
C. pleasurable                    
D. pleasureless

Choose the best answer for the following sentence:
San Diego is _______________ town in Southern California. 
A. more nice and nice                      
B. the nicer
C. the nicest                       
D. nicer and nicer

Choose the best answer for the following sentence:
Many people are not interested ____________ reading books as much as seeing films.
A. in                  
B. with                    
C. for                
D. about