B.Face scanning.

C.Fingerprint scanning.

D. Eye scanning.

29.What's a major problem of the iPhone X's Face ID system?

A.It often fails to recognize its owner's face.

B.Different faces could be used to unlock the same phone.

C.Face data could be used for other purposes.

D.It takes too long to unlock the phone.

30.What does Anil Jain think of biometric security?

A. It should be used with other security measures.

B.It has caused much trouble for police.

C.It's more secure than traditional measures.

D. It still needs much improvement.

31.The author wrote this article mainly to ______.

A.describe the popularity of biometrics

B.show how biometrics has changed our lives

C. point out various problems with biometrics

D. discuss the security problems of biometrics

Researchers in China and the United States have developed a new cataract(白内障)treatment with cells that has restored vision in babies in a trial and may eventually be used in adults. The treatment was published in March 9 edition of the scientific journal Nature.

A cataract is a clouding of the normally clear lens(晶体)of an eye. Typical cataract operation involves the removal of the cloudy lens and the insertion of an artificial one. The new operation has been tested in animals and during a small, human trial. It resulted in fewer complications(并发症) and in regrown lenses with superior visual function in all 12 of the baby cataract patients who received the procedure.

　A congenital cataract- lens clouding that occurs at birth or shortly after- is important cause of blindness in children. In the new research, Kand Zhang, head of ophthalmic genetics at US San Diego's Shiley Eye Institute, relied on the regrown potential of endogenous(同源的)stem cells.

　According to Zhang, endogenous stem cells are different from other stem cells that are typically grown in a laboratory. Zhang told CBS News, "We invented a new operation to make a very small opening at the side of a cataractous lens bag, remove the cataract inside, allow the opening to heal, and promote potential lens stem cells to regrow an entirely new lens with vision."

　　The human trial involved 12 babies under the age of 2 who were treated with the new method, while 25 babies received the standard operation care. The latter group experienced a higher incidence of post- operation danger. The scientists reported fewer complications and faster healing among the 12 babies.

32. Which is the best title?

A. The concept of the cataract

B. Bad effects of post-operation in the cataract

C. A new cataract treatment with stem cells

D. The popularity of a new treatment

33. Which of the following best describe the new cataract treatment according to the passage?

A. Convenient B. Comfortable C. Cheap D. Safe

34. What can we learn about the new cataract treatment?

A. It has more risks

B. It has been put into practice widely