Ứng với công thức C₉H₁₂ có bao nhiêu đồng phân có cấu tạo chứa vòng benzen ?

A. 9.

B. 7.

C. 6.

D. 8.

Read the following passage and mark A, B, C, or D to indicate the correct answer to each of the blanks.

EXAM ADVICE

In Part Three of the Speaking Section you work together with a partner. You have to do a (43)______ task which usually lasts about 3 minutes. One possible task is “problem solving”, which means you have to look at some (44)______information and then discuss the problem with your partner. You may be shown photos, drawings, diagrams, maps, plans, advertisements or computer graphics and it is (56) ______ that you study them carefully. If necessary, check you know exactly what to do by politely asking the examiner to repeat the instruction or make them clearer.

         While you are doing the task, the examiner will probably say very little and you should ask your partner questions and make (46) ______ if he or she is not saying much. If either of you have any real difficulties, the examiner may decide to step in and help. Normally, however, you will find plenty to say, which helps the assessor to give you a fair mark. This mark depends on your success in doing the task by competing with your partner, which includes taking (47) ______ in giving opinions and replying appropriately, although in the end it may be possible to “agree to disagree”.

Điền vào số (45)

A. essential

B. needed

C. helpful

D. successful

Một thanh AB có trọng lượng 150 N, có trọng tâm G chia đoạn AB theo tỉ lệ B G = 2 A G . Thanh AB được treo lên trần bằng dây nhẹ, không dãn (Hình 18.2). Cho góc , lực căng dây T có giá trị là

A. 75 N.

B. 100 N.

C. 150 N.

D. 50 N.

Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions

The old woman accused the boy _________ window

A. in breaking

B. on breaking

C. at breaking

D. of breaking