1 . Directions: Complete the following passage by using the words in the box. Each word can only be used once. Note that there is one word more than you need.

A. risky   B. solution   C. adaptation D. genetic   E. require F. definitely G. ruined   H. inconvenience   I. occur     J. qualify   K. completely

SEATTLE-For the more than 10 million Americans with colorblindness, there’s never been a treatment, let alone a cure, for the condition that leaves them unable to distinguish curtain colors.

Now, for the first time, two University of Washington professors have teamed with a California biotech firm to develop what they say may be a     1    : a single shot in the eye that can reveal the world in full color.

Jay and Maureen Neitz, who have studied the vision disorder for years, have found a new way to deliver genes that can replace missing color-producing proteins in certain cells, called cones, in the eyes.

The trouble will     2     when people are born without one or more of the three types of color-sensing proteins normally present in the cones of the retina (视网膜). The most common type is red-green colorblindness, followed by blue-yellow colorblindness. A very small proportion of the population is     3     colorblind, seeing only shades of gray.

Colorblindness is often a/an     4     disorder. It affects mostly men, who can inherit a mutation (变异) on the X chromosome (染色体) that weakens their perception of red and green. A much smaller part of cases are in women, who have two X chromosomes, which gives them a better chance of avoiding effects of any genetic imperfection.

Most people think of colorblindness as a/an     5     or disability, mainly causing problems with unmatched shirts and socks. But the Neitzes say the condition can have profound impacts-limiting choices for education or careers, making driving dangerous, and forcing continual     6     to a world designed for color vision.

“There are an awful lot of people who feel like their life is     7     because they don’t see color,” said Jay Neitz, 61, a professor, who confirmed in 1989 that dogs are colorblind, too.

People may not     8     as commercial pilots, for instance, if they’re colorblind. Other careers that can be restricted include those of chefs, decorators, electricians and house painters, all of which     9    detailed color vision.

Undoubtedly, the Neitzes’ findings have brought great benefits to those who are born unable to distinguish between red and green. But that technique is     10    , requiring surgery, so the Neitzes are looking for another way to do the job.