铣削长直齿齿条时,由于铣刀不能采用普通的铣刀轴安装在卧式铣床的主轴锥孔内,而必须采用万能立铣头或其它专用装置夹装夹铣刀。
参考答案:对
Aspirin is one of the safest and most effective drugs invented by man. The most popular medicine in the world today, it is an effective pain reliever. Its bad effects are relatively mild. It is also cheap.For millions of people suffering from arthritis, it is the only thing that works. Aspirin, in short, is truly the 20th-century wonder drug. It is also the second largest suicide drug and is the leading cause of poisoning among children. It has side effects that, although relatively mild, are largely unrecognized among users.Although aspirin was first sold by a German company in 1899, it has been around much longer than that. Hippocrates, in ancient Greece, understood the medical value of tree barks and leaves which today are known to contain a chemical found in aspirin. During the 19th century, there was a great deal of experimentation in Europe with this chemical, and it led to the introduction of aspirin. By 1915, aspirin tablets were available in the United States.A small quantity of aspirin relieves pain and inflammation. It also reduces fever by affecting some of the body’’s reactions. Aspirin is very irritating to the stomach lining. The best way is to chew the tablets before swallowing them with water, but few people can stand the bitter taste. Some people suggest crushing the tablets in milk or orange juice.
Which of the following statements is NOT true
A.Aspirin can relieve pain.
B.Aspirin can reduce fever.
C.Aspirin can relieve inflammation.
D.Aspirin can reduce stomach lining.
磨矿设备一般采用()。
A、破碎机
B、过滤机
C、筛分机
D、球磨机