Mark the letter A, B, C or D on your answer sheet to indicate the word or phrase that is OPPOSITE in meaning to the underlined and bold part in the following question.

Most universities have trained counselors who can reassure and console students who have academic or personal problems. 

A. sympathize 

B. satisfy 

C. discourage 

D. please 

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrases that best fits each of the numbered blanks.

Nowadays people are more aware that wildlife all over the world is in danger. Many species of animals will become (31)_____ if we do not make an effort to protect them. There are many reasons for this. In some cases, animals are (32) _____for their fur or for other valuable parts of their bodies. Some birds, such as parrots, are caught alive and sold as pets. For many animals and birds the problem is that their habitat - the place where they live - is (33) _____ . More land is used for farms, for houses or industry, and there are fewer open spaces than there once were. Farmers use powerful chemicals to help them grow better crops, but these chemicals pollute the environment and (34) _____ wildlife. The most successful animals on earth - human beings - will soon be the only ones (35) _____ , unless we can solve this problem

Điền ô số 33

A. exhausting 

B. departing

C. escaping

D. disappearing

Đốt cháy hoàn toàn hỗn hợp X gồm 2 ancol (đa chức, cùng dãy đồng đẳng) cần vừa đủ V lít khí O 2  (đktc). Sau phản ứng thu được 0,25a mol  CO 2  và 6,3a gam  H 2 O . Biểu thức tính V theo a là

A. V= 7,28a

B. V=14,56a

C. V= 4,48a

D. V= 8,96a

Điểm A ở đâu vậy bạn?

Gọi ƯC(n+1,2n+3)=d

Ta có: n+1 chia hết cho d=>2.(n+1) chia hết cho d=>2n+2 chia hết cho d

           2n+3 chia hết cho d

=>2n+3-(2n+2) chia hết cho d

=>2n+3-2n-2 chia hết cho d

=>1 chia hết cho d

=>d=Ư(1)=1

=>ƯC(n+1,2n+3)=1

Vậy phân số A tối giản