Lê Quỳnh  Anh

Read the following passage carefully and then choose the best answer to  each question.

As heart disease continues to be the number-one killer in the United States, researchers have become increasingly interested in identifying the potential risk factors that trigger heart attacks. High-fat diets and "life in the fast lane" have long been known to contribute to the high incidence of heart failure. But according to new studies, the list of risk factors may be significantly longer and quite surprising.

          Heart failure, for example, appears to have seasonal and temporal patterns. A higher percentage of heart attacks occur in cold weather, and more people experience heart failure on Monday than on any other day of the week. In addition, people are more susceptible to heart attacks in the first few hours after waking. Cardiologists first observed this morning phenomenon in the mid-1980, and have since discovered a number of possible causes. An early-morning rise in blood pressure, heart rate, and concentration of heart stimulating hormones, plus a reduction of blood flow to the heart, may all contribute to the higher incidence of heart attacks between the hours of 8:00 A.M. and 10:00 A.M.

           In other studies, both birthdays and bachelorhood have been implicated as risk factors. Statistics reveal that heart attack rates increase significantly for both females and males in the few days immediately preceding and following their birthdays. And unmarried men are more at risk for heart attacks than their married counterparts. Though stress is thought to be linked in some way to all of the aforementioned risk factors, intense research continues in the hope of further comprehending why and how heart failure is triggered.

Which of the following does the passage infer?

A. We have not identified many risk factors associated with heart attacks.

B. We now fully understand how risk factors trigger heart attacks.

C.  We do not fully understand how risk factors trigger heart attacks

D. We recently began to study how risk factors trigger heart attacks.

Dương Hoàn Anh
13 tháng 10 2019 lúc 5:26

C

Trong câu cuối: intense research continues in the hope of further comprehending why and how heart failure is triggered -> những cuộc nghiên cứu mở rộng vẫn tiếp tục trong hi vọng hiểu hơn lí do và cách thức gây ra suy tim -> vẫn còn cần nghiên cứu -> vẫn chưa hiểu đầy đủ

Bình luận (0)

Các câu hỏi tương tự
Lê Quỳnh  Anh
Xem chi tiết
Lê Quỳnh  Anh
Xem chi tiết
Lê Quỳnh  Anh
Xem chi tiết
Lê Quỳnh  Anh
Xem chi tiết
Lê Quỳnh  Anh
Xem chi tiết
Lê Quỳnh  Anh
Xem chi tiết
Lê Quỳnh  Anh
Xem chi tiết
Lê Quỳnh  Anh
Xem chi tiết
Lê Quỳnh  Anh
Xem chi tiết