One important outcome of the work on the expression of genes in developing embryos is sure to be knowledge that can help preventing birth defects. Just as promising (26) is the possibility of unraveling the complicated writing (27) of the brain. A mechanic gets valuable insight how an (28) automobile works by rebuilding car engines; similarly, neuroscientists can learn how the brain functions from (29) the way it is put together. The next step pursuing the (30) goal is to find out how the blueprint genes, the home box genes, control the expression of other genes that create the valves and piston of the working cerebral engine.

　　The protein encoded by the latter genes could change the (31) stickiness of the cell surface, the shape of the cell or its metabolism to create the characteristic peculiar to, say, neurons or neural-crest cell. Surface proteins may be the (32) mechanism, whereby similar programmed cells stick together to form specific structures; they might also sense (33)the local environment to help the cell decide what is to do.

　　Clarifying those mechanisms will engage the best talents in (34) embryology and molecular biology for some times to come. (35) What is perhaps the most intriguing question of all is if the brain is powerful enough to solve the puzzle of its own creation.

　　参考答案：

　　26.preventing 改为 prevent

　　27.complicated 改为 complexion

　　28.sight 后加 into

　　29.neuroscientist 改为 a neuroscientist

　　30.pursuing 后加 in

　　31.later 改为 latter

　　32.similar 改为 similarly

　　33.去掉 is

　　34.times 改为 time

　　35.if 改为 whether