Find a mistake in the four underlined parts of the sentence and correct it:
Where did you stayed in Paris?
A. Where
B. did
C. stayed
D. in Paris

Choose one sentence that has the same meaning as the root one:
I didn ’t expect them to invite me to the reception.
A. They weren’t expected to invite me to the reception.
B. I wasn’t expected them to invite to the reception.
C. I didn’t expect to be invited to the reception.
D. I wasn’t invited to the reception as I expected.

Choose one sentence that has the same meaning as the root one:
That is the man whom they were talking about in the office today.
A. They and that man had a talk in the office today.
B. The man and they were talking in the office today.
C. In the office today they were talking with that man.
D. They were talking about that man in the office today.

Choose the best answer for the following sentence:
_________ is the process of something becoming worse or weaker, or being made worse or weaker.
 
A. Competition               
B. Representative       
C. Entertainment              
D.  Degradation

Tổng của một cấp số nhân lùi vô hạn bằng $2$, tổng của ba số hạng đầu tiên của cấp số nhân bằng$\displaystyle \frac{9}{4}$. Số hạng đầu${{u}_{1}}$ của cấp số nhân đó là
A. ${{u}_{1}}=3.$ 
B. ${{u}_{1}}=4.$ 
C. ${{u}_{1}}=\frac{9}{2}.$ 
D. ${{u}_{1}}=5.$

A. -∞.
B. +∞.
C. 0.
D. Không tồn tại.

Tìm  để các hàm số  liên tục tại  
A.  
B.  
C.  
D. 1

Hàm số f(x)=x2-16x-4 khi x≠48 khi x = 4liên tục trên
A. R.
B. R\{4}.
C. (0; +∞).
D. a, b, c đều đúng.

Kết quả của giới hạn $\displaystyle \lim \frac{{{3}^{n}}-1}{{{2}^{n}}-{{2.3}^{n}}+1}$ bằng 
A. $\displaystyle -1.$ 
B. $\displaystyle -\frac{1}{2}.$ 
C. $\frac{1}{2}.$ 
D. $\displaystyle \frac{3}{2}.$

Giá trị của giới hạn $\lim \left( \sqrt{2{{n}^{2}}-n+1}-\sqrt{2{{n}^{2}}-3n+2} \right)$ là
A. $0.$ 
B. $\frac{\sqrt{2}}{2}.$ 
C. $-\infty .$ 
D. $+\infty .$