Một chất điểm chuyển động thẳng theo phương trình s = f(t) = t3 - 3t2 + 4t, trong đó S được tính bằng mét (m) và t được tính bằng giây (s). Gia tốc của chất điếm lúc t = 2s bằng:
A. 4 m/s2
B. 6 m/s2
C. 8 m/s2
D. 12 m/s2

Với hàm số f(x)=x3x-1. Tập nghiệm của phương trình f'(x)=0 là:
A. 0; 23
B. 0;- 23
C. 0; 32
D. 0; -32

Vi phân của hàm số sau: y = cosx.cos2x là
A. dy = (sinx.cos2x + cosx.sin2x)dx.
B. dy = (-sinx.cos2x - 2cosx.sin2x)dx.
C. dy = -2cosx.sin2x.dx.
D. dy = -sinx.cos2x.dx.

Choose the best answer for the following sentence:
Their parents are concerned _________ their bad behaviours. 
A. to                
B. for           
C. about                
D. of

Choose the best answer for the following sentence:
"Why do you look so tired?" - "Yes, I _____________ all night." 
A. was working                
B. worked
C. did work                 
D. have been working

Choose the best answer for the following sentence:
Son: "I have been familiar to the new learning environment." Father to Mother: "Our son said (that) he ___________ familiar to the new learning environment." 
A. had been              
B. has been                  
C. was being                
D. was

Choose the best answer for the following sentence:
Trees won’t grow __________ there is enough water.  
A. if           
B. when            
C. unless               
D.  as

Choose the best answer for the following sentence:
They were fortunate _________________ from the fire before the building collapsed.
A. rescuing           
B.  to have rescued 
C. to rescue                
D. to have been rescued

Choose the best answer for the following sentence:
Her ___________ was then terrible, and she could have hidden herself in a tomb.
A. elation                       
B. recovery                    
C. depression                         
D. encouragement

Choose the best answer for the following sentence:
If it _________ tomorrow, we may postpone going on a picnic. 
A. rains                
B. will rain               
C. shall rain              
D. raining