Trong các hình vẽ sau, hình nào mô tả đúng sự tạo ảnh của các gương?

Nếu sai, hãy giải thích lí do tại sao?

Read the followingpassage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 61 to 70.

    Harvard University, today recognized as part of ửie top echelon of the world’s universities, came from very inauspicious and humble beginnings.

    This oldest of American universities was founded in 1636, just sixteen years after The Pilgrims landed at Plymouth. Included in the Puritan emigrants to the Massachusetts colony during this period were more than 100 graduates of England’s prestigious Oxford and Cambridge universities, and these university graduates in the New World were determined that their sons would have the same educational opportunities that thev themselves had had. Because of this support in the colony for an institution of higher leaming, the General Court of Massachusetts appropriated 400 pounds for a college in October of 1636 and early the following ycar decided on a parcel of land for the school; this land was in an area called Newtown, which was later renamed Cambridge after its Ensiish cousitt and is the site of the present - day university.

    When a young minister namcd John Harvard, who came from the neighboring town of Charlestown, died from tuberculosis in 1638, he willed half of his estate of 1,700 pounds to the Aedslins college. In spite of the fact that only half of the bequest was actually paid, the General Court named the college after the minister in appreciation for what he had done. The amount of the bequest may not have been large, particularly by today’s standards, but it was more than the General Court had found it necessary to appropriate in order to open the college.

    Henry Dunster was appointed the first president of Harvard in 1640, and it should be noted that in addition to serving as president, he was also the entire faculty, with an entering freshman class of four students. Although the staff did expand somewhat, for the first century of its existence the entừe teaching staff consisted of the president and three or four tutors.

Question:The underlined pronoun “they” refer to________.

A. sons

B. educational opportunities

C. university graduates

D. Oxford and Cambridge universities

Một cửa hàng bán áo sơ mi, quần nam và váy nữ. Ngày thứ nhất bán được 21 áo, 21 quần và 18 váy, doanh thu là 5.349.000 đồng. Ngày thứ hai bán được 16 áo, 24 quần và 12 váy, doanh thu là 5.600.000 đồng. Ngày thứ ba bán được 24 áo, 15 quần và 12 váy, doanh thu là 5.259.000 đồng. Hỏi giá bán mỗi áo, mỗi quấn và mỗi váy là bao nhiêu ?

Giải các hệ phương trình sau bằng phương pháp thế:  x + 3 y = - 2 5 x - 4 y = 11

Tiến hành các thí nghiệm sau

(1) Cho dung dịch NH₃ vào dung dịch MgCl₂     (2). Sục khí SO₂ vào dung dịch H₂S

(3) Cho dung dịch AgNO₃ vào dung dịch NaF    (4) Cho kim loại Ba vào dung dịch H₂SO₄

(5) Cho kim loại Mg vào dung dịch FeCL₃(dư)

Sau khi kết thúc thí nghiệm, số trường hợp thu được kết tủa là

A. 3

B. 2

C. 5

D. 4