Polime nào sau đây được điều chế bằng phản ứng trùng ngưng?

A. Poli (etylen terephtalat)

B. Poliacrilonitrin

C. Polistiren

D. Poli (metyl metacrylat)

Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that best combines each of sentences in the following questions.

Question 50: She was irritated by her husband's lack of punctuality. She left him.

A. Being irritating by her husband's lack of punctuality, she left him.

B. She left her husband because of her irritation with his lack of punctuality.

C. Irritated by her husband, she punctually left him.

D. Irritating with her husband's lack of punctuality, she left him.

Nhỏ từ từ đến dư dung dịch Ba(OH)₂ vào dung dịch chứa m gam hỗn hợp Al₂(SO₄)₃ và Al(NO₃)₃. Sự phụ thuộc của khối lượng kết tủa (y gam) vào số mol Ba(OH)₂ (x mol) được biểu diễn bằng đồ thị bên. Giá trị của m là

A. 5,97

B.7,26. 

C.7,30 

D.5,88

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

My wallet_________at the station while I_______for the train.

A. must have been stolen/was waiting

B. should have stolen/had been waiting

C. will be stolen/am waiting

D. had to steal/would be waiting