相关考题
-
未知题型
Stomach ulcers are the cause ofsevere pain for many people. Doctors have been able to help lessen the pain ofulcers. They could not cure them Now doctors have discovered a cause of ulcers.This means they may have found a way to cure people who suffer from the stomachpain Studies show that ten percent of the popu-lation will develop an ulcer atsome time in their life. So a possible cure is good news for many people. Ulcers are wounds in thestomach that are similar to small cuts or tears. These wounds can harm the tis-sue in the stomach, the pipe that carries the food to the stomach or parts ofthe small intestines. Fluids in the stomach then increase the pain of an ulcer.How does a person know he or she has an ulcer? Doctors say most people withulcers feel a buming pain in their chest or stomach. This pain often is calledheart bunx It usually happens before eating or during the night. It causes somepeople to lose their desire to eat, or they are unable to keep food in theirstomachs. Doctors believed that ulcers were caused by unusualfy strong stomachfluids, which damaged stomach tissue. Now they have discovered that most ulcersare caused by a bacterial organism called Hillico Bactor Pilorie or HPillorie.HPillorie bacteria are what make stomach produce extra stomach fluid Doctorsfound that they can kill the bacteria with medicines called antibiotics. Healthexperts say the discovery of a cure for ulcers can save thousands of millionsof dollars in medical costs. They also believe curing ulcers will re- duce thenumber of people who develop stomach cancer. The number of people with stomachcancer is very high inJapan,Southeast Asia and parts of Africa. Doctors say a person is more likely to getan ulcer if his or her family has had one. In fact a person with the familyhistory of ulcers is three times more likely to get one than other people.There are ways people can protect themselves from developing an ulcer. Doctorssay it is more important to reduce the amount of strong fluids in the stomach.To do this, doctors say, people should not smoke cigarettes or drink alcohol.And they say people should reduce tension in their lives. In the past, doctors could not do anything about stomach ulcersA.RightB.Wrong C.Not mentioned
A.This
B.
C.How
D.HPillorie
E.
F.There
G.To
H.And
I.
J.Right
B.Wrong
K.Not -
未知题型
如果i=2.5cos(2πt-30°)A，求当u为下列表达式时，i与u的相位差，二者超前或滞后的关系如何? (1)u=120cos(2πt+10°)V； (2)； (3)u=-10cos2πt V； (4)u=-33.8sin(2πt-28.6°)V。
A.5cos(2πt-30°)A，求当u为下列表达式时，i与u的相位差，二者超前或滞后的关系如何?
B.174.24.96:6088/Latex/latex.action?latex=dT00MHNpbigyXHBpIHQtXGZyYWN7XHBpIH17M30pVg%3D%3D' -
单项选择题
（）对于诚信相当于不可一世对于（）。
A.出尔反尔；谦虚
B.背信弃义；谦让
C.过河拆桥；谦逊
D.忘恩负义；谦卑
