Đốt cháy hoàn toàn m gam một triglixerit X cần 9,016 lít O₂, thu được 6,384 lít CO₂ và 4,77 gam H₂O. Mặt khác, m gam X phản ứng vừa đủ với x gam Br₂ (trong dung môi CCl₄). Biết thể tích các khí đo ở điều kiện tiêu chuẩn. Giá trị của x là       

A. 4,0.

B. 3,2.

C. 4,8.

D. 1,6.

The majority of primary school teachers  ______ women.

A. is 

B. are 

C. includes  

D. including

Tính (bằng định nghĩa) đạo hàm của mỗi hàm số tại các điểm đã chỉ ra: y   =   1 x tại  x 0   =   2

Thuỷ phân hết 7,612 gam hỗn hợp X gồm hai este đơn chức và hai este đa chức cần dùng vừa hết 80ml dung dịch gồm KOH aM và NaOH 0,80M, thu được hỗn hợp Y gồm muối của các axit cacboxylic và các ancol. Đốt cháy hoàn toàn hỗn hợp Y, thu được muối cacbonat, 4,4352 lít CO₂ (đktc) và 3,168 gam H₂O. Giá trị của a là

A. 1,60.

B. 1,65.

C. 0,80.

D. 0,85.

Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that need correction in each of the following questions
Alike light waves , microwaves may be reflected and concentrated elements.

A. Alike

B. waves

C. may be

D. concentrated

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

Farmers depend on meteorologists. They need meteorologists’ accurate forecasts for successful agricultural planning

A. Due to meteorologists’ accurate forecasts, farmers depend on them for successful agricultural planning

B. Farmers depend on meteorologists who need their accurate forecasts for successful agricultural planning

C. Farmers need meteorologists’ accurate forecasts for successful agricultural planning and so they depend on you

D. Farmers depend on meteorologists, whose accurate forecasts they need for successful agricultural planning

Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that is closest in meaning to each of the following questions.

 “Why don’t you ask your parents for advice?” said Tom

A. Tom advised me asking my parents for advice

B. Tom said to me to ask my parents for advice

C. Tom wanted to know the reason why I don’t ask my parents for advice

D. Tom suggested that I ask my parents for advice

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 18 to 22.

We all want to live in a clean and green world and breathe pollution free air. For this kind of environment we desperately need a fossil fuel free world. Scientists are toiling hard to come up (18)______ alternative fuels which can replace conventional fuels. One such study was presented at the 237th National Meeting of the American Chemical Society. This study throws interesting light on the first economical, eco-friendly process to (19)______ algae oil into biodiesel fuel. The scientists are quite hopeful that one day America will become independent (20)______ fossil fuels. Ben Wen is the (21)______ researcher and vice president of United Environment and Energy LLC, Horseheads, N.Y. According to him, “This is the first economical way to produce biodiesel from algae oil. It costs much less than conventional processes because you would need a much smaller factory, there (22)______ no water disposal costs, and the process is considerably faster.”
Question 18:

A. to

B. against

C. with

D. for