Qua thời gian, mục tiêu hợp tác của Hiệp hội các nước Đông Nam Á đã thay đổi như thế nào?

Xenlulozơ trinitrat là chất dễ cháy và nổ mạnh, được điều chế từ xenlulozơ và axit nitric. Thể tích axit nitric 47,5% có khối lượng riêng 1,52 g/ml cần để sản xuất 53,46 kg xenlulozơ trinitrat nếu hiệu suất đạt 90% là

A. 47,12 lít

B. 52,36 lít

C. 49,74 lít

D. 44,76 lít

Read the following passage and mark the letter A, B, C or D on you answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 1 to 5.

How men first learnt to (1) ........ words is unknown; in other words, the origin of language is a mystery. All we really know is that men, unlike animals, (2) ............ invented certain sounds to express thoughts and feelings, actions and things so that they could communicate with each other; and that later they agreed (3) ........... certain signs, called letters, which could be combined to represent those sounds, and which could be written down. These sounds, (4) .......... spoken or written in letters, are called words. Great writers are those who not only have great thoughts but also express these thoughts in words that a peal powerfully to our minds and emotions. This charming and telling use of words is what we call literary (5) ........... Above all, the real poet is a master of words.

Điền ô số 3

A. at

B. upon

C. with

D. to