Why did it take so long to develop the X-ray microscope?
A. Funds for research were insufficient
B. The source of illumination was not bright enough until recently
C. Materials used to manufacture X-ray tubes were difficult to obtain
D. X-ray microscopes were too complicated to operate
Giải bởi qa.haylamdo.com
Giải thích:
Tại sao lại mất nhiều thời gian để phát triển kính hiển vi tia X?
A. Kinh phí cho nghiên cứu không đủ
B. Nguồn chiếu sáng không đủ sáng cho đến gần đây
C. Vật liệu dùng để sản xuất ống tia X rất khó kiếm được
D. Kính hiển vi tia X quá phức tạp để vận hành
Thông tin: In recent years, however, interest in X-ray microscopes has revived, largely because of advances such as the development of new sources of X-ray illumination. As a result, the brightness available today is millions of times that of X-ray tubes, which, for most of the century, were the only available sources of soft X-rays.
Tạm dịch: Tuy nhiên, trong những năm gần đây, sự quan tâm về kính hiển vi tia X lại được khơi lại một cách rộng rãi bởi vì các sự tiến bộ ví dụ như sự phát triển của nguồn mới về độ chiếu sáng của tia X. Kết quả là, ánh sáng có sẵn ngày nay là hàng nghìn lần các tia X nối ống với nhau, cái mà hầu hết thế kỉ là nguồn duy nhất có sẵn của tia X mềm.
Chọn B.
Aristotle believed that everything in the universe were composed of four basic elements: earth, water, air, and fire.
When they give you the contract, please ________ the document before you sign it.
Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.
What ________ at 9 o'clock last night? I phoned you but couldn't get through to you.
The first half of the game was pretty boring because the players did not take enough effort.
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- Burt: "Why didn't you show up for class this morning?"
- Kevin: “__________. You know, I live far from the school."We've been together through ________ in our friendship, and we won't desert each other now.
Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions.
The Native Americans would not allow anyone to trespass on their sacred burial ground.
Mark the letter A, B, C, or D on your answer sheet to indicate the word that differs from the other three in the position of primary stress in each of the following questions.
