Trong số các polime : [HN-(CH₂)₆-CO-(CH₂)₄-CO-]_n (1) ; [-NH-(CH₂)₅)-CO-]_n (2)  ; [-NH-(CH₂)₆-CO-]_n (3) ; [C₆H₇O₂(OOCCH₃)₃]_n (4) ; (-CH₂-CH₂-)_n (5) ; (-CH₂-CH=CH-CH₂-)_n (6) ; [-CH₂-CH(CN)-]_n (7). Polime được dùng để sản xuất tơ là

A. (1); (2); (3); (4).

B. (2); (3); (4).

C. (1); (2); (3); (4); (7).

D. (1); (2); (3); (7).

C quần áo ấm. Trùng hợp chất nào sau đây tạo thành polime dùng để sản xuất tơ nitron

A. CH 2 = CH - CN

B.  CH 2 = CH - CH 3

C.  H 2 N - [ CH 2 ] 5 - COOH

D.  H 2 N - [ CH 2 ] 6 - NH 2

Mark the letter A, B, C, or D on your answer sheet to indicate the word whose underlined part differs from the other three in pronunciation in each of the following questions

A. attracts

B. delays

C. believes

D. begins

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 31 to 37.

   A gesture is an action that sends a message from one person to another without using words. We use gestures to communicate with others. There are some gestures that have completely different meaning depending on when and where they are used.

   When an American wants to show that something is OK. or good, he raises his hand and makes a circle with his thumb and foreigners. The circle sign has only one meaning for him. He might be surprised to learn that in other countries it can mean something different. In Japan, for instance, it is the gesture for money. In France, it means 'zero' or 'worthless'. Such differences can lead to all kinds of misunderstanding when foreigners meet. But why is it that the same gesture has so many different meanings?

   When some people want to show that something is exact or precise, they make a sign to show that they are holding something between the tips of their thumb and forefinger. Many people from all over the world do this when they want to make a specific point as they are speaking. People later started using this signal to mean 'exactly right' or 'perfect'. This was how the famous OK was bom.

   In Japan, money means coins and coins are around. Therefore, making a round hand sign came to represent money. It is simple as that. The French sign for 'nothing' or 'worthless' also has a simple origin. This time the circle doesn't represent a coin, but nought. Nought equals zero, zero equals nothing, nothing equals worthless.

What does the circle sign represent in France?

A. It means money.          

B. It means coins

C. It means something exact.

D. It means useless

BẦU ƠI THƯƠNG LẤY BÍ CÙNG

SAU NÀY CŨNG SẼ NẤU CHUNG MỘT NỒI

không phải sai đây mới là đúng ĐI MỘT NGÀY ĐÀNG TỐN BA MƯƠI NGÀN TIỀN XĂNG thế mới đúng chứ

lick hộ nhé

để cứu đói chủ tịch hồ chí minh đã kêu gạo cả nước lập hủ gạo cứu đói ĐÓ LÀ CHỐNG GIẶC ĐÓI con GIẶC RỐT là phong trào xóa nạn mù chữ đã được phát động khắp nơi trường học được mở thêm trẻ em nghèo được cắp sách tới lớp