Mỗi bạn học sinh giỏi sẽ được thưởng 5 quyển vở. Hỏi để chuẩn bị phát phần thưởng cho 10 bạn như vậy thì cô giáo cần mua bao nhiêu quyển vở ?

A. 15 quyển vở

B. 50 quyển vở

C. 5 quyển vở

D. 10 quyển vở

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 30 to 34.

     Body language is a vital form of communication. In fact, it is believed that the various forms of body language contribute about 70 percent to our comprehension. It is important to note, however, that body language varies in different cultures. Take for example, eye movement. In the USA a child is expected to look directly at a parent or teacher who is scolding him/her. In other cultures the opposite is true. Looking directly at a teacher or parent in such a situation is considered a sign of disrespect.

     Another form of body language that is used differently, depending on the culture, is distance. In North America people don't generally stand as close to each other as in South America. Two North Americans who don't know each other well will keep a distance of four feet between them, whereas South Americans in the same situation will stand two to three feet apart. North Americans will stand closer than two feet apart only if they are having a confidential conversation or if there is intimacy between them.

     Gestures are often used to communicate. We point a finger, raise an eyebrow, wave an arm – or move any other part of the body – to show what we want to say. However, this does not mean that people all over the world use the same gestures to express the same meanings. Very often we find that the same gestures can communicate different meanings, depending on the country. An example of a gesture that could be misinterpreted is sticking out the tongue. In many cultures it is a sign of making a mistake, but in some places it communicates ridicule.

     The dangers of misunderstanding one another are great. Obviously, it is not enough to learn the language of another culture. You must also learn its non-verbal signals if you want to communicate successfully.

Which form of body language is NOT mentioned in the passage?

A. posture

B. gesture 

C. distance

D. eye movement

Cho hỗn hợp  K 2 C O 3 và  N a H C O 3 (tỉ lệ mol 1:2) vào bình  B a H C O 3 2 thu được kết tủa X và dung dịch Y. Thêm từ từ dung dịch HCl 0,5M vào bình đến khi không còn khí thoát ra thì hết 560 ml. Biết toàn bộ Y phản ứng vừa đủ với 190 ml dung dịch NaOH 1M. Khối lượng kết tủa X là

A. 9,85 gam     

B. 8,865 gam     

C. 7,88 gam     

D. 17,73 gam