B

　　In reading science，　 a heading （标题）often gives a clue （线索）to a problem that is going to be discussed .Getting the problem clearly in your mind is the first step to take in studying such material. You are advised to do this in reading science articles.

　　1. Read the title and think about it .

　　2. Read all of the headings .You should get a clear idea of what the problems are without reading anything but the headings.

　　3. Next ，　read the article all the way through carefully. Each time you come to a heading that names a problem， read the paragraphs under that heading to find out ： 1. more information about the problem；　2.how the problem may be met .

　　41. This passage offers advice on _______.

　　A. how to read titles and headings B. how to find headings in an article

　　C. what problems to be discussed in science article

　　D. how to read science material

　　42. It is advisable for you ________.

　　A. to read the heading which you think is the title

　　B. to read the heading that names a problem

　　C. to read one heading and the paragraph under it each time

　　D. to read the headings only

　　43. Read the whole article after ________.

　　A. you have got all the information about the problem

　　B. you understand the title C. you have read one paragraph after another

　　D. you are clear about what to be discussed

　　44. You read the whole article carefully _________.

　　A. to get all the headings B. to see how the problem is discussed

　　C. to name problems D. to think about the title