Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase thet best fits each of the numbered blanks from 31 to 35.

 In the western customs (31) _______ hands is the customary form of greeting, but in China a nod of the head or (32) _______ bow is sufficient. Hugging and kissing when greeting are uncommon. Business cards are often (33) _______ and yours should be printed in your own language and in Chinese. Also, it is more respectful to present your card or a gift or any other article using (34) _______ hands. The Chinese are (35) _______ applauders. You may be greeted with group clapping, even by small children.

Điền ô số 34

A. pair

B. couple

C. double

D. both

Cho peptit : H₂N-CH₂-CO-NH-CH(CH₃)-CO-NH-CH(CH₃)-CO-NH-CH₂-CO-NH-CH₂-COOH. Thủy phân hoàn toàn peptit trên thu được bao nhiêu amino axit khác nhau? 

A. 5 

B. 3 

C. 2 

D. 4 

GIẢI HỘ CÁI

Khi thủy phân hết pentapeptit X (Gly–Ala–Val–Ala–Gly) thì thu được tối đa bao nhiêu sản phẩm chứa gốc glixyl mà dung dịch của nó có phản ứng màu biure? 

A. 4. 

B. 2. 

C. 3.

D. 5.