* Bản chất hóa học của gen là ADN ; gen là 1 đoạn của phân tử ADN có chức năng di truyền xác định; mỗi gen có 600–> 1500 cặp nu. * Chức năng của gen : chủ yếu gen mang cấu trúc là một đoạn mạch của phân tử ADN, mang thông tin quy định cấu trúc của một lại Pr nhất định.

Was it really necessary that I _____ there watching you the entire time you were rehearsing for the play? It was really boring watching you repeat the scenes over and over again

A. am sitting 

B. be sitting 

C. being sitting 

D. sitting 

Cho các hợp chất có cùng công thức phân tử C₉H₈O₄, đều chứa hai chức este dưới đây.

Số chất khi thủy phân hoàn toàn trong dung dịch NaOH, thu được ba sản phẩm hữu cơ là

A. 3

B. 1

C. 4

D. 2

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 23 to 27.

My first job was a sales assistant at a large department store. I wanted to work part-time, because I was still studying at university and I was only able to work a few nights a week.

I came across the advertisement in the local newspaper. I remember the interview as though it were yesterday. The (23)______ manager sat behind a large desk. He asked me various questions which surprised me because all I wanted was to work in sales. An hours later, I was told that I had got the job and was given a contract to go over. I was to be trained for ten days before I took my post. Also, as a member of staff, I was (24) to some benefits, including discounts.

When I eventually started, I was responsible (25) ______ the toy section. I really enjoyed it there and I loved demonstrating the different toys. I was surprised at how friendly my colleagues were, too. They made working there fun even when we had to deal with customers (26) _____ got

on our nerves. (27) ______, working there was a great experience which I will never forget.

Question 25

A. for

B. with

C. in

D. to